High Speed Inductive eRPS Sensor Error Reduction Using COMSOL Multiphysics®
COMSOL European Conference 2023
J.-D. Wheeler1, T.Chauchard2, F.Nieceron2, P.Namy1, J-M. Dedulle1, B.Varoquie2
1 SIMTEC, 5 rue Felix Poulat, Grenoble, (France)
2 CONTINENTAL AUTOMOTIVE France SAS, Av Paul Ourliac, Toulouse, (France)
Modern electrical vehicle motors require a precise current control over the rotation of the rotor. These motors have high performance, but their control requirement impose a precise knowledge of the rotor angular position.
Rotor position sensor (RPS) are traditionally designed using magnets which are dependent of complex supply chains. The present study is dedicated to a magnet-less inductive RPS dedicated to electrical motors (Inductive eRPS), and thus able to provide rotor position at high speed.
The present analysis showcases the design process of a new Inductive eRPS. The design process uses numerical simulation to optimize the sensor accuracy under realistic component assembly conditions.
A numerical model is proposed by SIMTEC to investigate different realistic assembly imprecisions. It solves the Maxwell-Ampère equation in the air, the target, and the coils. The magnetic vector potential is used together with the magnetic scalar potential for the sake of efficiency.
Thanks to experiments run at CONTINENTAL Automotive, the angular error prediction precision is assessed thoroughly, and the numerical model is validated for industrial use.
Heat Transfers and Solid Mechanics in Microarchitectured Materials using Periodic Homogenization
COMSOL European Conference 2023
F.Viry1, J.-D. Wheeler1, P.Namy1
1 SIMTEC, 5 rue Felix Poulat, Grenoble, (France)
Microarchitectured materials are generally made of different compounds bound at the microscopic level using a periodic pattern. This results in a macroscopic material with new properties arising from each of the individual compound properties and the way the microarchitecture binds them.
The periodic microstructure can then be optimized to obtain specific macroscopic material properties, but attention must be paid to the microstructure response, such as high thermal gradients in heat transfers or mechanical stresses in structural mechanics.
Using a finite element analysis to forecast such behaviors is often computationally challenging due to the abundance of geometrical details, leading to a large number of degrees of freedom to solve for. Modelers must then rely on more sophisticated numerical methods.
This paper studies the use of the periodic homogenization method in heat transfers and solid mechanics. This method has the advantage to be built upon a well-established mathematical basis.
The initial problem is reformulated into two-scale finite element problem. At the microstructure-scale, unitary stimulations of the material are performed in order to characterize homogenized properties of the material. At the part-scale, homogenized temperature or displacement fields are solved. Each of these steps requires to solve far less degrees of freedom than the initial problem.
Ultimately, both results are combined by relocation in order to get an accurate prediction of the local temperature, conductive fluxes, displacement and mechanical stresses.
Modelling the Heat Dissipation of a Head Lamp within COMSOL Multiphysics®
COMSOL European Conference 2023
F.Viry1, P.Namy1, C.Dupuis2
1 SIMTEC, 5 rue Felix Poulat, Grenoble, (France)
2 DECATHLON B'twin Village, Lille, (France)
In order to reduce the environmental footprint of a serial production of head lamps, one lever is to replace and employ new materials, often requiring to redesign the product to ensure its mechanical and thermal resistance.
In this context, this paper studies the modelling of the heat dissipation of a head lamp within COMSOL Multiphysics®. The electronic components of the lamp produce heat by Joule effect, modelled as thermal sources. Within the lamp, the three heat transfer modes are modelled. The heat conduction is modelled in volumes using the Heat Transfer in Solids physics, and shell elements for thin volumes (e.g. the copper layout). Natural convection is modelled using the Nonisothermal Laminar Flow interface. The radiative transfers are taken into account using the Surface-to-surface Radiation physics. The heat transfers of the lamp with the surrounding environment are modelled using heat transfer coefficients for natural convection and radiative losses.
To validate the model, experimental results are available on an existing lamp. When the lamp is open, temperature distributions are available thanks to thermal camera measurements, allowing a qualitative validation of the model. The model is then validated quantitatively in the closed lamp configuration using temperature measurements available thanks to thermocouples placed within the lamp.
The model can then be used as a digital twin to assess the heat dissipation performance of new designs by forecasting the temperature field and the hot spots within the lamp.
Towards Accurate Modelling of Aeraulic Droplets Interactions within COMSOL Multiphysics®
COMSOL European Conference 2023
F.Viry1, M.Sturma2, P.Namy1, B.Barbet2
1 SIMTEC, 5 rue Felix Poulat, Grenoble, (France)
2 MARKEM-Imaje, Bourg-lès-Valence, (France)
In the field of industrial marking, continuous inkjet technology is based on high speed emission of ink drops. The printing quality is directly linked to the interactions of the droplets with their environment during flight time: electric field, aerodynamic perturbations, and droplet-droplet interactions.
In a former paper, all these interactions were modelled in a fully coupled Lagrangian-Eulerian approach within COMSOL Multiphysics®. Particularly, aeraulic interactions between droplets were obtained thanks to the air flow induced by all the droplets by resolving Navier-Stokes equations. Numerical simulations were compared to experimental data, showing a good agreement in terms of flight time and macroscopic position of the droplets on the printed medium but also inaccuracies in the gap between droplets, leading to a biased forecast of the printing quality. Resolving accurately the surrounding air flow requires in fact an extremely fine mesh.
This paper studies another approach to take into account the aeraulic interactions between two droplets using abacuses. First, steady air flows around a unique droplet are computed using the Laminar Flow physics of COMSOL Multiphysics® for multiple droplet velocities. Second, these results are combined within interpolation functions in order to get an abacus of the air velocity field around each droplet. Finally, this abacus is integrated in the Particle Tracing physics of the former model to estimate the drag force experienced by each droplet in the air flow induced by the other one, replacing the computation of Navier-Stokes equations in the surrounding air.
This new approach makes it possible to forecast phenomena of aeraulic aspiration followed by bouncing of the droplets by electrostatic repulsion, allowing a better understanding of the mechanisms and the design parameters playing on the printing quality.
Modelling of Droplet Charge Dynamics during an Ink Jet Breakup using COMSOL Multiphysics ®
COMSOL European Conference 2023
M.Sturma1, A.Monlon2, P.Namy2, F.Viry2, B.Barbet1
1 MARKEM-Imaje, Bourg-lès-Valence, (France)
2 SIMTEC, 5 rue Felix Poulat, Grenoble, (France)
Continuous Ink Jet (CIJ) printing technologies are widely used in the field of industrial coding and marking. These technologies are based on the emission of a high-speed jet of ink droplets (20 m/s) onto the surface of a moving medium. To maintain sufficient print quality, it is essential to control the positions of the droplets on the printing medium. The position of each droplet depends on several factors, including the quality of the jet breakup, the charge carried by each droplet, the deflection of the droplets in an electric field, and their interactions in flight. Numerical modelling can provide detailed information at each step, allowing to predict the behavior of ink droplets, and ultimately helping to design CIJ printheads.
This article focuses on modelling the droplet charging process between electrodes during ink jet breakup in COMSOL Multiphysics®. The dynamics of the ink jet surrounded by air is modelled using the two-phase flow Level Set interfaces from the Fluid Flow module. The spatial charge is modelled using the Electric Current (EC) physics from the AC/DC module. With a particular attention to the timestep, numerical simulations can be used to predict the charge embedded in each droplet just before the breakup, and therefore the embedded charge in each droplet that is deflected after breakup. This model also allows to apprehend the historical charge distributed along the following droplets.
The prediction of the uncharged jet breakup dynamics is assessed thanks to experiments ran at MARKEM-Imaje, validating the CFD part of the model, and providing confidence in using the charging model for industrial use.
Designing a Numerical Modeling of Induction Brazing
COMSOL European Conference 2023
V. Bruyere1, C.Durand2, S.Roure2, P.Namy1
1 SIMTEC, 5 rue Felix Poulat, Grenoble, (France)
2 SCHNEIDER ELECTRIC, Eybens, (France)
Induction brazing is a widely used joining process in various industries, offering efficient and localized heating for the assembly of diverse components.
At Schneider Electric®, this process is used to assemble a silver piece on a copper piece. This work focuses on the advancements and insights gained through the development of a 3D thermal and electromagnetic model with Comsol Multiphysics®.
A surface impedance method was used to describe the electromagnetic field in the metal parts. To control the electric power, a global ODE has been added to the problem. Moreover, a strong coupling between electromagnetics and thermal equations has been considered because of the strong variations of electrical conductivity with temperature. Finally, parametric studies have been performed to study the influence of the power cycle and the position of the assembled pieces.
Designing a Satellite Component Assembly Resistant to High Vibrational Stress using COMSOL Multiphysics®
COMSOL European Conference 2023
V. Mesle1, J.-D. Wheeler2, M. Jouan1, V. Bruyere2, J. Leost1, L. Couteleau1
1 RAKON France SAS, 2 rue Robert Keller, Pont-Sainte-Marie (France)
2 SIMTEC, 5 rue Felix Poulat, Grenoble, (France)
RAKON is a worldwide expert in high performance crystal oscillator. The company decided to expand its product range to larger space equipment, the Master Reference Oscillator (MRO). This product is composed of stacked mechanical modules, joined together by structural screwed assemblies.
During the launch to enter orbit, this equipment is subject to high acceleration and stress, well defined by space standards and products specifications.
Numerical analyses are required to ensure the design of such screwed assembly. For that, RAKON extensively assesses their devices under representative conditions. To guarantee the most realistic model possible, a precise determination of the structure’s physical parameters and an adaptation of the screwed assembly analysis methodology is required.
In this paper, an experimental analysis is performed by RAKON with the help of SIMTEC to assess the damping behaviour of the mechanical structure. The quality factors are first determined, and then numerically implemented in an acceleration spectral density (ASD) analysis model, representing the random vibrations imposed on the system.
Those numerical simulations are traditionally ran using legacy software, which are not always adapted for complementary analysis. The versatility of COMSOL Multiphysics® gives a better control of condition’s analysis. By upgrading the software’s physics readily available spring elements with rotation degrees of freedom, SIMTEC proposes a method finely adapted to RAKON’s needs.
This changes in COMSOL Multiphysics® are the opportunity to validate the mechanical behaviour of structural screwed assembly under vibrational stress.
Numerical Simulation of Laser Lithotripsy
COMSOL European Conference 2023
A.Menaesse1, V. Bruyere2, P. Namy2, V.Gatineau1, S.Giovanni1
1 EMS, Ch. de la Vuarpillière, 31CH-1260 Nyon, (Switzerland)
2 SIMTEC, 5 rue Felix Poulat, Grenoble, (France)
The use of lasers to fragment and remove kidney stones (Laser Lithotripsy) has become increasingly popular in surgical procedure due to its high success rates and minimal side effects. However, the precise mechanisms behind the stone fragmentation process are not yet fully understood. The objective of this work is to develop a numerical model to determine the dimensions of the crater (depth, width) generated by the application of a laser on a study material (stone). Given the complexity of the mechanisms involved, a simplified approach is proposed to treat the formation of the crater from a threshold temperature and by using a deformed geometry. The numerical results obtained are then compared to experimental results for different fiber widths and several energies to validate this numerical approach.
MicroScopic and MacroScopic Modeling of Non-Isothermal Flow through Porous Media
COMSOL European Conference 2023
T.Paris1, V. Bruyere2, P. Namy2, D.Rochais3, S.Chupin3
1 CEA Valduc, Is-Sur-Tille, (France)
2 SIMTEC, 5 rue Felix Poulat, Grenoble, (France)
3 CEA, Le Ripault, Monts, (France)
Macroscopic modeling of fluid flow and thermal diffusion, in a porous medium, requires the description of equivalent properties (permeability, conductivity and diffusivity). However, depending on the microstructure topology of the porous medium and the fluid flow regime at the microscopic scale, great disparities in equivalent properties values can be obtained. The aim of this work is to describe, at the microscopic scale, thermal diffusion and fluid flow for different regimes and quantify how microstructural properties influence macroscopic effective response. After importing the microstructure on a representative volume element (RVE), 2D and 3D strategies are compared. Results are then discussed with literature data and equivalent phenomenological model comparison to validate the numerical approach.
Numerical Optimization of Electroactive Actuator Position for Optical Mirror Applications
COMSOL European Conference 2023
K.Thetpraphi1,3, V. Bruyere2, D.Audigier1, J.F.Capsal1, P. Namy2, G.Moretto3
1 Univ Lyon, INSA-Lyon, LGEF, EA682, F-69621, Villeurbanne, (France)
2 SIMTEC, 5 rue Felix Poulat, Grenoble, (France)
3 Centre de Recherche Astrophysique de Lyon (CRAL), 9 avenue Charles André, 69230 Saint-Genis-Laval, (France)
Electroactive actuators are widely used in precision optical systems to control the position and shape of optical elements, such as telescope mirrors. However, the optimal position of the electroactive actuator for a given optical mirror design is not obvious, and numerical optimization techniques can be employed to find the optimal solution.
To control the local curvature of the mirror and to define the objective to minimize in the optimization procedure, a first distributed ODE is implemented. In a second step, a mechanical model is developed to compute the mirror displacement as a function of the force applied by the piezoelectric actuators. Finally, an optimization procedure is used to minimize the local curvature by controlling the intensity and distribution of the electromechanical force.
The optimized results show a strong interest in the use of this technology to minimize the initial defects related to the manufacturing of the mirror or the defects during use related to the gravity creep.
Modelling of the Ladle Furnace Preheating with a Graphite Heating Rod
COMSOL European Conference 2023
S.Semenov1, P.Namy1, M.Sievers2, B.Friedrich2, V.Djupvik3, K.Blandhol3
1 SIMTEC, 38000 Grenoble, (France)
2IME Process Metallurgy and Metal Recycling, RWTH Aachen University, Aachen, (Germany)
3 Elkem Technology, Kristiansand, (Norway)
This work, which is done in the framework of the SisAl Pilot EU project, presents the use of COMSOL Multiphysics® for simulating ladle furnace preheating.
The SisAl Pilot project aims at optimising the silicon production in Europe by recycling materials and using a carbon-emission friendly technology. The silicon production experiments are conducted on laboratory and pilot scales in different types of furnaces, including ladle furnaces. Besides experimental work, the process optimisation also relies on the numerical modelling.
The present model simulates the preheating of an existing ladle furnace with a graphite heating rod used as a resistive element powered by a DC electric current. The aim of the work is to tune unknown problem parameters, especially graphite properties, by fitting experimental temperature curves. The adjusted material properties will be further used in the SisAl Pilot project for the numerical analysis of new ladle furnace designs.
In general, the graphite properties, such as density, heat capacity, thermal and electrical conductivity, are functions of temperature and can vary depending on the material type and supplier. In the present study, we assume that the heating rod graphite and the crucible graphite differ from each other only by their porosity. With this assumption, a single set of temperature-dependent graphite properties, found in literature, can be generalised by modulating it with the material's porosity according to a preferred analytical model (Landauer's relation in this work). This makes porosity a single tuning parameter for each type of graphite in the model.
The experimentally measured electric current through the heating rod serves as a known model input parameter. Measured electric power and temperatures are used for the model tuning and validation. The following COMSOL® modules are employed in this model: Heat Transfer in Solids and Fluids with convectively enhanced gas conductivity, Surface-to-Surface Radiation, and Electric Currents to simulate the Joule effect in electrically conducting materials. A bidirectional coupling of all the modules is present due to multiple interdependencies via material properties.
The proposed numerical model has successfully simulated the ladle furnace preheating. The work is validated against experimental data: the tuning of model and material parameters has resulted in a satisfactory fitting of experimental curves. The adjusted graphite properties are ready to be exploited in the next stage of the SisAl Pilot project, which is focussed on the numerical analysis of new furnace designs. The presented approach of tuning material properties can be applied to other problems dealing with porous materials.
Modelling of an ensemble averaged electric arc in a laboratory-scale electric arc furnace
COMSOL European Conference 2023
S.Semenov1, P.Namy1, M.Sievers2, B.Friedrich2
1 SIMTEC, 38000 Grenoble (France)
2 IME Process Metallurgy and Metal Recycling, RWTH Aachen University, Aachen, (Germany)
This work, which is done in the framework of the SisAl Pilot EU project, presents the use of COMSOL Multiphysics® for simulating an ensemble averaged electric arc in a laboratory-scale electric arc furnace.
SisAl Pilot project aims at optimising the silicon production in Europe by recycling materials and using a carbon-emission friendly technology. The silicon production experiments are conducted on laboratory and pilot scales in different types of furnaces, including electric arc furnaces (EAF). Besides experimental work, the process optimisation also relies on the numerical modelling.
The present model simulates the furnace preheating and the initial slag melting in a laboratory-scale EAF, in which a DC electric arc operates between a graphite cathode and the anode formed by a thin layer of slag at the bottom of the graphite crucible.
The main difficulty is associated with modelling the heat source due to the electric arc operation. There are various complex physical processes involved in the arc, including the plasma physics, induced high-velocity gas flow, and radiant and convective heat transfer towards the electrodes and the crucible. The channel-arc model is a commonly used approach for a simplified 0D simulation of the electric arc behaviour in a variety of applications.
Being used in this model, it estimates the temperature and gas velocity in the arc column. At each moment in time, this 0D model provides an instantaneous spatial distribution of heat sources in the furnace relative to an immediate arc position. Additional modelling complication stems from the fact that the instantaneous electric arc is constantly changing its position on a very short time scale by jumping from one place to another. On average, it occupies the whole space under the graphite cathode. Thus, an ensemble averaging of the arc position is performed to obtain integral expressions of the averaged arc radiation and of the averaged Lorentz force that drives the gas flow in the plasma region. These integrals are evaluated in part analytically, and in part numerically. The experimentally measured electric potential difference and dissipated power are used as model input parameters.
The following COMSOL® modules are employed in this model: Heat Transfer in Solids and Fluids with phase change, Turbulent Flow k-E model in gas and liquid slag phases, Surface-to-Surface Radiation, Electric Currents to simulate the Joule effect in electrically conducting materials, Deformed Geometry to simulate variable electric arc shape, and Global and Domain ODEs to compute quantities associated with the ensemble averaging of the electric arc. A bidirectional coupling of all the modules is present due to multiple interdependencies.
The averaging of the arc position helps to deconcentrate and redistribute heat sources, which results in plausible material temperatures and demonstrates the expected initial slag melting. The model can be further used to optimize furnace operation in terms of predicting possible thermal damages or heat losses and increasing the raw material melting efficiency. The presented ensemble averaging approach can be applied to other electric arc problems with a similar geometry.
Modeling of Thermal Expansion and Metallurgical Phases of a Material
during its Cooling
COMSOL European Conference 2023
A.Clarissou1, V. Bruyère2, P.Namy2, I.Crassous1
1 FRAMATOME, 73400 Ugine, (France)
2 SIMTEC, 38000 Grenoble (France)
In metallurgy, the use of numerical models is popular because of the many coupled physical phenomena that occur during the various processes. For instance, the resulting shape and metallurgical state of a material are very sensitive to changes in temperature.
The ingot cooling leads to thermal contraction : the thermal exchanges are drastically affected by the quality of contact between the metallic ingot and the crucible. To better understand these phenomena, a 2D axisymmetric model is developed using COMSOL Multiphysics® to simulate the casting and cooling of an ingot in a crucible.
The casting process is carried out until the ingot has reached its final height, and then the ingot is cooled for several hours by water flowing over the crucible walls. By using a moving mesh method to describe the growth of the ingot, a thermo-mechanical model is built which includes the metallurgic phases evolution. After numerical validation, this model can be used to predict the influence of thermal contact resistances at the external walls of the ingot on the temperature and shape evolution of a material during casting.
The metallurgical phase composition of the metal ingot is directly influenced by its thermal history over time and the properties of each potential phase change : this model can be used to describe the evolution of the different metallurgical phases during the cooling.
Numerical Simulation of Electron Beam Welding
COMSOL European Conference 2023
P.O. Barrioz1 , V. Bruyère2 , P. Namy2 , A. Brosse1
1 Framatome Lyon (France)
2 SIMTEC, 38000 Grenoble (France)
Electron beam welding process is a high energy welding technique that uses a focused beam of electrons to join metal components. It is widely used in various industries, due to its ability to produce high quality welds with minimal distortion and heat input. However, this process involves numerous parameters that can affect the final weld quality, making it challenging to optimize and control.
A thermohydraulic model is developed to describe the dimensions of the melted zone and the resulting shape of the free surface on a geometry with chamfers. A level set approach is used to study the influence of surface tension and Marangoni effects on the shape of the weld pool. After adapting the solvers, the influence of the mesh and numerical parameters is studied, and results are discussed.
3D Numerical Simulation of Resistance Sintering Process for Electrical
Contact Applications for Breakers
COMSOL European Conference 2023
J. Amovin-Assagba1, V. Bruyère2, P. Namy2, C. Durand1, S. Roure1
1 SCHNEIDER ELECTRIC, Eybens (France)
2 SIMTEC, 38000 Grenoble (France)
In circuit breakers, short-circuit breaking involves extreme conditions linked to the presence of an intense electric arc. This requires the use of specific electrical contacts consisting of a contact tip made of composite materials, assembled on a metallic substrate.
SCHNEIDER ELECTRIC uses the resistance sintering technique for the sintering-assembly of silver-based composite electrical contact materials on copper substrates. It is a fast-sintering technique that combines heat generated by an electrical current and pressure to densify powder metallurgy parts. A variety of properties are required for the electrical tips (High electrical and thermal conductivity, good welding resistance, good densification state...).
To control the resulting geometry as well as the final states of the sintering process, a 3D electro-thermo-mechanical model has been developed using COMSOL Multiphysics. Thanks to accurate knowledge of material properties and contact resistances, this numerical model is a predictive tool of these different final states, which can lead to better product quality. In our paper, we will describe the 3D model, the numerical modeling strategy and present also some obtained results.
Numerical Modelling of Aluminothermic Reduction for Low-carbon-footprint Silicon Production
I3M 2022
S.Semenov1, R.Bayle1, P.Namy1
1 SIMTEC, 38000 Grenoble (France)
Silicon production usually employs carbon to reduce quartz. A new process using secondary aluminium instead of carbon, and, thus avoiding producing carbon dioxide, is currently being studied. Two immiscible phases are involved in the process, a metal phase, initially composed of aluminium, and a slag phase, initially composed of a mix of lime and quartz.
Present numerical work studies different phenomena that contribute to the reaction kinetics, namely diffusion, soluto-gravitational convection and thermo-soluto-gravitational convection. The impact of forced convection on the global reaction rate is also studied. For this purpose, two numerical models, including chemical, thermal and fluid dynamics aspects, are developed: a model where the metal-slag interface is fixed and explicitly represented and a diffuse interface model.
The models are numerically solved using the finite element method within the software COMSOL Multiphysics®. The proposed methodology is totally new due to modelling of all physical phenomena in a fully coupled way.
The aim of this work is to gain insight into the phenomena contributing to the global reaction rate, which is a critical parameter to control in the silicon production process. The novelty of approach consists in assessing the impact of individual phenomena by incrementing progressively the complexity of models.
Modelling of a Multifunction Electromagnetic Interference Shield and Heat Exchanger Device for a Multirotor Drone
I3M 2022
JD.Wheeler1, N.Texier2, M.Malara1, T.Sanlaville2, V.Seconda2, VSousselier2, JM.Dedule1, P.Namy1
1 SIMTEC, 38000 Grenoble (France)
2 PARROT DRONE SA, Paris (France)
Whereas the processing capacity of multirotor drone increases significantly, the specification applying to the hardware to dissipate the heat becomes more challenging. At the same time, the weight must be reduced, and the electromagnetic vulnerability must still be prevented.
In this study, the authors aim at increasing the performance of the drone by taking advantage of new material properties and a science-based approach. A numerical model of the heat transfers in the drone is developed using COMSOL Multiphysics®. Moreover, two specific analytical models from the literature are identified and solved to predict the shield performance. Thanks to the physic predictions, it is possible to determine the minimum material quantity to achieve the best performances. Design guidelines are derived for the engineers to develop the next generation of multirotor drones.
Modelling of the Rinsing of a Fixed Bed Reactor for Solid Phase Peptide Synthesis using COMSOL Multiphysics®
I3M 2022
R.Bayle1, JD.Wheeler1, R.Ravetti2, P.Namy1, O.Ludemann-Hombourger2
1 SIMTEC, 38000 Grenoble (France)
2 POLYPEPTIDE GROUP, Strasbourg (France)
Solid Phase Peptide Synthesis (SPPS) requires finely designed reactor. While the process itself is tuned during a lab-scale procedure, the scale-up to production size reactor opens new challenges. The efficiency of the reaction and the quality of the final substance can be made like the lab-scale results, but it requires to master the critical scale up parameters.
In this study, the process design is secured by using a numerical model. The fluid flow in the whole reactor and more specifically in the fixed resin bed during the draining steps is modelled in a realistic way through Brinkman equation and the appropriate boundary conditions. Using this computed fluid flow, the rinsing of the reactor can be studied by modelling the reagents to eliminate with particles whose trajectories are driven by the previously computed fluid flow.
Contact Resistance Influence in Numerical Simulation of Resistance Sintering
I3M 2022
J.Amovin-Assagba1, V.Bruyère2*, P.Namy2, C.Durand1, S.Roure1
1 SCHNEIDER ELECTRIC, Eybens (France)
2 SIMTEC, 38000 Grenoble (France)
* Lead Author
Resistance sintering is a fast-sintering process used to compact and form a metallic part thanks to heat and pressure. To better control the geometry of the sintered material, a multi-physical model has been developed. To describe the current flow, the thermal exchanges and the mechanical aspects, this model requires the use of precise material properties as well as the knowledge of contact resistances. Indeed, these parameters are of first importance to describe the energy distribution in the system and the resulting metallurgical state.
Different approaches have been compared in this work to study their influence on the values of interest. By considering the contact resistances as a function of pressure and temperature, this full 3D multi-physical approach offers a new tool to precisely predict the geometry of the resulting assembly.
Electrostatic and Aerodynamic Modelling of the Charged Droplet Trajectories thanks to a Lagrangian-Eulerian Model in COMSOL Multiphysics®
19th International Multidisciplinary Modeling & Simulation Multiconference
F.Viry1, M.Stuma2, P.Namy1, B.Barbet2
1 SIMTEC, 38000 Grenoble (France)
2 MARKEM-IMAJE, Bourg-Lès-Valence (France)
In the field of industrial marking, continuous inkjet technology is based on high speed emission of ink drops. The printing quality is directly linked to the interactions of the droplets with their environment during flight time: electric field, aerodynamic perturbations, and droplet-droplet interactions.
To model all the physics, a fully coupled model is developed within COMSOL Multiphysics®. Dynamics of droplets are modelled by coupling a particle tracing approach – lagrangian approach – to a continuous eulerian one. For the particle dynamics, the Coulomb force, the Lorentz force and the drag forces, dependent on the air velocity, are considered. The surrounding air is itself driven by the movement of the other droplets, and is modelled by the Navier-Stokes equation in an eulerian approach.
This paper shows the development of a continuous inkjet printhead so called digital twin, providing a decision-making tool to ensure the stability of the ink raster.
Optimization of the Drying Time of Industrial Solvents: Numerical Modelling within COMSOL Multiphysics®
19th International Multidisciplinary Modeling & Simulation Multiconference
F.Viry1, M.Stuma2, P.Namy1, B.Barbet2
1 SIMTEC, 38000 Grenoble (France)
2 MARKEM-IMAJE, Bourg-Lès-Valence (France)
In the field of industrial inkjet marking, the drying time to evaporate the solvent is a key factor of the process productivity. In order to optimize it, a new approach of the drying process is assessed numerically in this paper. An air blade is used to push away the newly evaporated solvent to reduce the local solvent partial pressure.
Therefore, it maximizes the vaporization flux. This idea is implemented within the software COMSOL Multiphysics®. The air flow is computed through the Navier-Stokes equation, and the solvent concentration is modelled by a convection-diffusion equation. The vaporization profile is assessed in several configurations. Eventually, the numerical results show that the air blade reduces dramatically the drying time.
By this way and given a drying time in industrial environment, one can consider a broader family of solvent, i.e. less volatile solvent compared to so called MethylEthylKetone.
Modelling of the Melt Pool Behaviour during a Pulsed Tig Welding Operation in a Narrow Groove
13th International Seminar Numerical Analysis of Weldability
S.Cadiou*1, A.Baumard1, A.Brosse1 V.Bruyère2
1 Framatome-DTIM, Lyon (France)
2 SIMTEC, 38000 Grenoble (France)
* Lead Author
Arc welding is one of the main processes for assembling metal components in the nuclear industry. To guarantee the quality of the welded assemblies and to predict the characteristics of the weld, it is necessary to master the welding process and have a thorough understanding of the interactions within the melt pool.
To this end, the objective of this work is to develop a transient numerical model allowing for the prediction of the behaviour of the melted zone during current pulsation in reasonable computational times. The relevant industrial application in this study is the welding of a narrow groove gap of a stainless steel pipe. The welding process used is pulsed TIG and different synergies are studied. In this work, numerical simulation is used as a predictive analysis tool providing data that complete the experimental ones. Knowing that the predictive aspect of the simulations depends on the modelling choices, it is necessary to consider the main physical phenomena governing the melt pool (thermal transfers, fluid flow, electromagnetism) and to model the mass feeding process using the Arbitrary Lagrangian Eulerian (ALE) method. The development of the magneto-thermohydraulic model with material supply is carried out using the Comsol Multiphysics® software
Impact of a Strong Electromagnetic Field on Rebars in a Reinforced Concrete Building : Design Guidelines and Safety Assessment
NAFEMS WORLD CONGRESS 2021
J.-D.Wheeler1, A.Arnold2, E.Sassine1, E.Chevallier1, P.Namy1
1 SIMTEC, 38000 Grenoble (France)
2 OMEXOM, Lyon (France)
To design installation close to high-power AC electromagnetic device, a prediction of the electromagnetic coupling may be mandatory. The present device is composed of different high current multi-turn coils located near the installation, a conductor mesh. This study investigates the self-inductances of the different coils and the mutual inductances to assess the electromagnetic coupling within the installation.
Besides, the study also focuses on the Eddy currents (induction currents) in the conductor mesh around the coil: such currents can be rather large if the appropriate precautions are not used. Such large current may create unwanted significant heat rise in the mesh: it is induction heating. Construction guidelines are then identified and used to design a safe installation.
Coupled Membrane-free Optical Microphone and Optical Coherence Tomography keyhole measurements to setup welding laser parameters
SPIE LASE 2020
N.Authier,1 E.Touzet,1 F.Lücking,2 R.Sommerhuber,2 V. Bruyère,3 P.Namy3
1 CEA (France)
2 Xarion Laser Acoustics GmbH (Austria)
3 SIMTEC, 38000 Grenoble (France)
The measurement of depth of a laser capillary in industrial conditions by Optical Coherence Tomography technique is demonstrated in this work.
This paper highlights the results achieved by the recent combination of ultrasound sensitive membrane-free optical microphone by XARION and PRECITEC’s OCT IDM system.
Joint interpretation of the ultrasound spectrograms and the digging curves of the keyholes enables better understanding of the dynamics of the melted metal and determination of the ideal welding parameters.
Cooling Process Optimization Through a Three-Phases Thermo-Hydraulic Model
COMSOL European Conference 2020
J.-D. Wheeler1, M. Pautard2, T. Gilloux2, P. Namy1, C. Coulouarn2
1 SIMTEC, 38000 Grenoble, France
2 THALES
In order to optimize the industrial “ammunition cooling” process, a COMSOL Multiphysics® model is proposed. A shell body filled with a melt-cast explosive formulation is poured and cooled by circulation of a heat transfer fluid.
The solidification of the explosive composition has several thermal and fluidic consequences. To account for the solidification enthalpy, the “modified heat capacity” method is introduced to the model. Besides, the solid and liquid phases have very different densities. This results in convection within the liquid explosive composition part which requires solving the Navier-Stokes equations under their weakly compressible form. The free surface of the mixture varies thanks to a moving mesh, and the solid phase is modelled through a zero velocity in the Navier-Stokes equations.
The cooling process ensures a controlled loss of heat throughout the shell, from its bottom to its top. This allows for a continuous and unique solidification front. The top of the shell is maintained above the solidification temperature whereas the bottom of the device is cooled by pulsed air or water. Thanks to the simulation results, the industrial process has been optimized by reducing the cooling time and improving quality.
The app previously developed in 2017 has been improved to account for the physical phenomena which are introduced. COMSOL Server™ enables a remote computing to the users, thanks to an https secured internet connexion.
Modelling of an Innovative Directional Ultrasonic Atherosclerosis Treatment Device
COMSOL European Conference 2020
JD.Wheeler1, V. Bruyere1, N. Aeby2
1 SIMTEC, 38000 Grenoble, France
2 Designer of the service
Atherosclerosis prevalence keeps increasing worldwide because of the sedentary lifestyle and aging of the population. It is a pathology which is characterized by the build-up of plaque on the artery walls. While it has no incidence at the beginning, the blood flow can be severely altered in the most advanced cases. Atherosclerosis can lead to lethal consequences.
Several methods can be used to allow for a normal blood flow recovery; they are known as angioplasty. Whereas some of them rely on the flattening of the plaque, many atherosclerosis require to be properly removed. The removal can be made by different methods including ultrasonic waves.
The present article introduces a modelling of the latter method and focuses on the generation of the ultrasonic waves which produces cavitation. Whereas existing angioplasty ultrasonic devices producing cavitationhave a single degree of freedom and generate a cavitation field only in one direction, the present device is driven not by only one piezoelectric actuator but by three independent piezoelectric actuators (patented concept). Therefore, the generated cavitation field can be oriented and focused on specific areas of the artery wall and better target the plaque.
The model includes a coupling between the ultrasonic tip mechanical movement and the acoustical behaviour of the aqueous environment surrounding the tip. The acoustical field allows for a precise prediction of the cavitation generation and the Rayleigh-Plesset equation provides predictions of the bubble’s dynamic.
Thanks to the simulation results, a proof of concept was established and the directional abilities of the device have been optimised.
Modeling of Charged Droplet Dynamics in an Electric Field using COMSOL Multiphysics®
COMSOL European Conference 2020
M.Sturma1, P.Namy2, V. Bruyère2 , B.Barbet1
1 MARKEM-IMAJE Industries
2 SIMTEC, 38000 Grenoble, France
In the field of coding and industrial marking areas, CIJ technology is based on high speed emission of ink drops (20 m/s) which are directed onto a moving printing medium.The printing quality depends, on one hand, on drops position on the media determined by thedrop charge and the electrostatic field, and on the other hand, on the position accuracy which depends on unwanted drops interaction in flight (electrostatic repulsion and aerodynamic effects). For instance, in a 24-points matrix, there are 2^24 combinations which cannot be predetermined experimentally. COMSOL Multiphysics enables to model these coupled effects in order to predict the location of a drops line on the medium, and this way, to create an aid to design CIJ printer heads. First, the 2D electrostatic field, defined mainly by the electrodes geometry, is computed thanks to the AC/DC module. Then, the particle tracing module is used to compute the droplet trajectory in the electrostatic field by modelling the droplet as a charged material point subjected to the Lorentz force and the Coulomb one. This electrostatic repulsion, describing the droplet-droplet electrostatic interaction, is taken into account thanks to the particle tracing module.This paper describes the coupled model which allow to compute droplets trajectory until the prediction of droplet positions on the printing media. Numerical results are compared to experimental data to validate the predictions quality and the model as a design support tool.
Experimental and numerical simulation of pits on a corroded 316L grade stainless steel
COMSOL European Conference 2020
E.Sassine1, J.Rosec2, V.Bruyère1, R.Fargere2, P.Namy1
1 SIMTEC, 38000 Grenoble, France
2 Naval Group, Bouguenais, France
Corrosion is an ongoing issue in metallurgic field. Stainless-steel products are likely to corrode in certain environmental conditions, especially if they are exposed to marine environment where localized corrosion can occur. The aim of this work is to study the behavior of 316L grade stainless steel subjected to pitting corrosion in a marine solution. The originality of this paper is that chemical kinetics parameters used in numerical simulation are based on experimental campaign in artificial seawater. Pitting initiation mechanism is not be treated in this paper and the main interest is focused on pits development. 2D Axisymmetric simulations in transient mode were accomplished thanks to COMSOL Multiphysics® software. The analysis of the experimental measurements indicates that mean width and depth of pits are relatively close, so pits can be considered as a hemisphere. Numerical results show that pit propagation depends on its initial form. A hemispherical pit keeps its shape during propagation (only its radius increases over time) while an ellipsoid pit has a different behavior.
Optimizing your Femtosecond Laser Processes using a Numerical Simulation based Decision Support Tool
COMSOL European Conference 2020
E.Chevallier1, V.Bruyère1, G.Bernard2, P. Namy1
1. SIMTEC, 38000 Grenoble, France
2. GFMS, Meyrin, Switzerland
The use of ultrashort regime in laser ablation is increasing in industries as it allows better precision and reduces the heat affected zone of each impact. In this paper, a finite element model of the femtosecond laser matter interaction is presented. The aim of this model is to inform the laser user on the topography that will be obtained given the laser parameters selected, such as average power, pulse duration, frequency, etc. At these timescales, the classic temperature modelling approach cannot be used as the system is not at equilibrium. The two-temperature model is used to capture the heating of the electrons during the first period followed by the diffusion of the electron energy to the lattice. The model is calibrated against experimental topography data, width and depth of the crater, extracted from literature. A linear extrapolation to predict the depth, width and ablated volume of the crater is proposed and its validity within 10% is assessed for impacts created with up to 1000 pulses.
Modeling of the Magnetic Field in a Vacuum Arc Remelting Furnace using COMSOL Multiphysics®
COMSOL European Conference 2020
V. Bruyère1, P.Namy1, I.Crassous2, F. Alex2, C. Deville-Cavellin2
1 SIMTEC, 38000 Grenoble, France
2 FRAMATOME, 73400 Ugine, France
The vacuum arc remelting is a refining process used to melt reactive metals like titanium, zirconium or hafnium. Melting is performed under vacuum to avoid reactions between liquid metal and oxygen which could be a source of pollution. This process is particularly well suited to purify impurities at high temperature and to minimize the segregation. Therefore, the company Framatome used it to produce Zirconium alloys dedicated to nuclear fields and medical fields. The VAR process consists in applying a current intensity between a zirconium electrode and the mold intended to receive the melted metal. An electric arc occurring between these two electrodes enables the bottom of the zirconium electrode to melt and fill in the mold. The cooled mold is usually made of copper and equipped with coils to apply an electromagnetic stirring. The control of the process is essential to ensure quality through chemical composition and structural homogeneity. For this reason, Framatome and Simtec companies have developed the modeling of the magnetic field in a vacuum arc remelting furnace using COMSOL Multiphysics®. This model is especially used to check the capacity of the system to ensure a homogeneous magnetic field for different melt parameters of different products. The evolution of the calculated magnetic field is discussed for different current intensities and compared with experimental values. The good agreement between the calculated and experimental results allows to improve both the coils design and the control of the process.
A User-Friendly COMSOL Multiphysics® Application to Design a Generic Induction Furnace
COMSOL European Conference 2020
O.Brun, J.-D.Wheeler, J.-M.Dedulle, V.Bruyère, P.Namy
SIMTEC, 38000 Grenoble, France
Metallurgical process of metal melting requires tremendous amounts of energy. A modern way to optimise the power required is to use an induction furnace. Such furnaces are efficient but more challenging to design and to run than a conventional device.
In order to design an induction furnace and to optimize the charge melting, a COMSOL Multiphysics® application is developed. This application runs a furnace electromagnetic model. The inductor, supplied with an alternative electrical current, creates a variable induction field B. Due to this field, an induced current appears in the melt and in the crucible. Thus, the charge starts to heat up. The input current frequency, the inductor properties and the melt material have a huge impact both on the heat quality and the meshing refinement required by the simulation. This application provides a user-friendly interface to easily set up a furnace configuration. The whole model is fully adaptable to most configurations. From the inductor electric supply circuit to the geometrical air gap size between the inductor and the crucible, most parameters are available to the user within the interface. Then, the mesh adapts itself to consider the specific requirements of the magnetic simulation field. This remeshing step is computed in a completely transparent manner for the user.
Using a 2D axisymmetric formulation, configurations can be solved to quickly provide post processing results based on concrete industrial needs, such as the power distribution in the charge or the global efficiency of the equipment.
Numerical Simulation of Electro-Thermo-Mechanical Phenomena During Resistance Sintering
COMSOL European Conference 2020
S.Bourdon1, P.Rogeon2, V.Bruyère3, P.Namy3, C.Durand1, S. Roure1
1SCHNEIDER ELECTRIC, EYBENS, France
2Univ. Bretagne Sud, IRDL, LORIENT, France
3SIMTEC, 38000 Grenoble, France
Resistance-sintering can be used in a powder metallurgy process as the heating step toconsolidate a metallic compact previously obtained by pressing a powder-alloy. This fast-sintering process consolidates electrically conductive powders by simultaneous application ofpressure and electrical current. An electro-thermo-mechanical model has been developed tosimulate an industrial process involving silver-based electrical contacts composites. A transientnumerical approach is used to solve this strong coupled problem. Specific laws, establishedthanks to extensive experimental characterizations, are implemented to describe the physicalproperties evolutions and the mechanical behavior of the composites during sintering. Finally,the numerical model is able to predict the dimensions and properties of the final sintered part.
From the laser parameters to the tribological properties with COMSOL Multiphysics®
COMSOL European Conference 2019
V. Bruyère¹, J-D Wheeler¹, P. Namy¹
¹ : SIMTEC, Grenoble, France
In this work, the authors compare two different approaches to obtain the topography of laser texturation. Their aim is to demonstrate their strengths and weaknesses when being used as input data in a fluid lubrication model able to take into account non smooth surfaces. The first method consists in including the height distribution stemming from topography measurements. The second is rather different and deals with the numerical predictions of the topography. Indeed, SIMTEC has developed a thermo-hydraulic model to quantitatively predict the shape of the laser crater. The output of such a model is a prediction of the topography.
The lubrication results obtained with the numerical predictions are presented, together with the strengths and difficulties of both methods.
Multi-scale modelling of a reacting flow through a porous bed using COMSOL Multiphysics®
COMSOL European Conference 2019
S. Bouchex-Bellomie1, T. Paris1, V. Bruyère2, P. Namy2, J. M. Dedulle2
¹: CEA Valduc, 21120 Is sur Tille, France
²: SIMTEC, 38000 Grenoble, France
Using the software COMSOL Multiphysics based on the finite element method, a one-dimensionnal model has been developped to predict the transient behaviour of a gas flow through a porous bed. The problem is solved at a macroscopic scale, therefore, the porous bed is seen as a continuum with adapted equations such as Darcy’s law. Because the gas phase is composed of different species, diffusive effects are taken into account. The solid matrix is composed of a metal which can absorb gas within its lattice. Therefore, chemical exchanges occur between the gaseous species and the species initially loaded in the solid phase. The chemical exchange is assumed to be rate-limited by the surface exchange taking place at the gas and solid phases interface. Thermal effects are also taken into account and coupled with the others mechanisms (convection, diffusion and chemical reaction). Finally, numerical results have been compared with experimental data from the litterature.
Femto-second laser texturing prediction using COMSOL Multiphysics®
COMSOL European Conference 2019
E.C. Chevallier¹, V. Bruyère¹, G. Bernard², P. Namy¹
¹: SIMTEC, Grenoble, France
²: GFMS, Meyrin, Switzerland
Femto-second laser texturing offers the possibility to reduce significantly the amount of molten material. This means better surface properties as well as more accurate prediction of the surface topography. At SIMTEC, we developed a 2D time dependent model. The ultra-short deposition of the energy is taken into account in this model through an approach called the “two-temperature model”, which consists in modelling the Thermalization of the electrons followed by the energy transfer from the electrons to the lattice.
In this article, we review the range of pulse duration requiring the use of this two-temperature model. The results show that for pulses lower than several tens of picoseconds, the lattice and electron temperature are significantly different indicating the need to use the two-temperature model. This is in accordance with physical phenomena description of ultrashort laser impacts.
When Precise Numerical Predictions Come to the Rescue of Liquid Lubrication
COMSOL European Conference 2018
J. D. Wheeler¹, V. Bruyere¹, P. Namy¹
1. SIMTEC, Grenoble, France
Whereas some bearings designed in the 19th century are still working properly nowadays, some more recent ones encountered premature failures. Tribological applications, such as journal bearings or rolling element bearings, are ruled by complicated multiphysical phenomena.
An appropriate numerical model is one of the most efficient mean to better understand the physics of these applications. Such a model involves the solving of the Reynolds equation. At high loads, solid deformations may also play a role. The contact would then follow an elasto-hydrodynamic behaviour. Moreover, the lubricant shearing is very likely to generate a significant heat which should be accounted for.
A simple tribological model, the lubricated pad, is presented in this article. Its goal is to address the different challenges that may be involved under different working conditions. A COMSOL application based on the model developed for this tribology case is also developed. It is run with COMSOL Server™.
Free Surface Deformation of the Weld Pool in Orbital Narrow Gap GTA Welding
COMSOL European Conference 2018
S. Morville¹, V. Bruyère², P. Namy²
¹ Technical Center FRAMATOME, France
² SIMTEC, Grenoble, France
Arc current welding is a widespread process in heavy industry for the assembly of metallic components. In order to ensure the good quality of welded assemblies, it is appropriate to master the welding process but also to have a deep understanding of interactions with the weld pool and resulting characteristics. Numerical simulation is used as a predictivein situ analysis tool which provides additional data to real-time measurements. It involves taking into account heat transfer and fluid flow inside the melt pool, but also electromagnetic phenomena induced by the electrical arc. For that purpose, a 3D steady-state model is implemented with energy, momentum, mass and current conservation equations and by taking into account the deformation of the free surface with an ALE method. Marangoni effect, Lorentz forces and Buoyancy are also included. Results are in good agreement with the state-of-the-art knowledge.
Finite Element Prediction of Laser-Material Interaction using COMSOL Multiphysics®
COMSOL European Conference 2018
E.C. Chevallier¹, V. Bruyère¹, TianLong See², P. Namy¹
¹. SIMTEC, Grenoble, France
². Manufacturing Technology Centre (MTC), United Kingdom
Surface engineering is a key technology used in a wide range of sectors in industry. Among other techniques, it involves adding functionality to a surface. The objective of the work presented in this paper is to build an application using COMSOL Multiphysics® to predict the topography produced given the set of laser parameters as well as the material properties of the sample to be textured.
The application of the model is twofold. First, the influence of the laser parameters such as power, frequency and impact duration on the final topography is assessed. Then, an application is created using the Application Builder so the surface topography prediction can be integrated in a laser machine, enabling the future user to predict the topography of one laser impact on its sample, using COMSOL Server™. The topography is further used in the machine to predict the surface functionality of the sample (wettability, friction coefficient etc.).
Influence of a Porous Corrosion Product Layer on the Corrosion Phenomenon of Carbon Steel Pipelines
COMSOL US Conference 2018
M. Mohamed-Saïd¹, P. Namy¹
¹SIMTEC, Grenoble, France
Assessing the severity of the internal corrosion of structures is of paramount importance in the oil & gas industry. Considerable effort has been deployed to implement an adequate electrochemical process of the corrosion phenomenon. However the influence of transport phenomenon trough a porous corrosion product layer (CPL) on the corrosion rate has not been studied extensively yet.
The transport phenomenon can influence the corrosion rate significantly by either limiting or accelerating the cathodic contribution. In this paper the general corrosion of a carbon steel under a porous CPL of siderite is studied and the influence of the transport phenomenon is examined using COMSOL Multiphysics ®. This model constitutes a first step and can be used for further development in order to assess the effect of either, a competitive diffusion trough a CPL or a conductive CPL, on the corrosion phenomenon.
Adaptive Mesh Refinement: Quantitative Computation of a Rising Bubble using COMSOL Multiphysics®
COMSOL European Conference 2018
T. Preney¹, P. Namy¹, J. Wheeler¹
1. SIMTEC, Grenoble, France
To accurately measure the variation of the unknowns, a relevant mesh should have a high density of degrees of freedom in regions where the norm of the gradient of the quantity of interest is significant. Fine meshes, on the other hand tend to induce long computational times, especially when complex 3D physics (fluid mechanics, electromagnetism …) are involved. The Adaptive Mesh Refinement (AMR) method implemented in COMSOL Multiphysics® can help to mitigate computational time while maintaining precision. Instead of using a fixed mesh throughout the simulation, the initial mesh is adapted to the solution while the simulation is computed.
In this paper, the rising of a gas bubble in a liquid is modelled with the finite element (FE) software COMSOL Multiphysics® using a two-phase flow approach. Results from literature are compared with results obtained using both fixed and adaptive meshes. The results from the AMR method available in COMSOL Multiphysics® are then compared with results obtained with different software: NaSt3D and OpenFOAM.
Manufacturing of Dysprosium-Iron Alloys by Electrolysis in Fluoride-Based Electrolytes. Electrolysis in a Laboratory-Scale Cell
Metall. Mater. Trans. 2018
A. M. Martinez1, K. S. Osen1, A. Støre1, H. Gudbrandsen1, O. S. Kjos1, A. Solheim1, Z. Wang1, A. Oury2, P. Namy2
1. SINTEF Industry, Sem Saelands vei 12, 7465 Trondheim, Norway
2. SIMTEC, Grenoble, France
Electrolytic production of light rare earth elements and rare earth alloys with transition elements takes place in a fluoride-based electrolyte using rare earth oxides as raw material. The optimization of this method, mainly in terms of the energy efficiency and environmental impact control, is rather challenging. Anode effects, evolution of fluorine-containing compounds and side cathode reactions could largely be minimized by good control of the amount of rare earth oxide species dissolved in the fluoride-based electrolyte and their dissolution rate. The Dy2O3 feed rate needed for stable cell operation was studied by following up the anode voltage and gas analysis. On-line analysis of the cell off-gases by FTIR showed that the electrochemical reaction for the formation of Dy-Fe alloy gives mainly CO gas and that CF4 is starting to evolve gradually at anode voltages of ca. 3.25 V. The limiting current density for the discharge of the oxide ions at the graphite anode was in the range of 0.1 to 0.18 A cm2 at dissolved Dy2O3 contents of ca. 1 wt pct. Modeling of the laboratory cell reactor was also carried out by implementing two models, i.e., an electrical model simulating the current density distribution at the electrodes and a laminal bubbly flow model that explains the electrolyte velocity induced by gas bubble production at the anode.
Compressible Flow Modeling Occurring in a Depressurization Process
COMSOL European Conference 2017
V. Bruyere1, T. Paris2, F. Viry1, P. Namy1
1 SIMTEC, 8 rue Duployé, Grenoble, 38100 France
2 CEA DAM, Valduc, Is-sur-Tille, France
The depressurization process is the emptying of one tank to another one through a pipe network. In order to optimize the design of pipes and tanks, a good knowledge of the gas flow behavior is required. The modeling of compressible flows with a Mach number near 1 is quite challenging and simplifications are necessary to create an efficient numerical tool. Thus, a simple model is developed here, using COMSOL Multiphysics® and the “Non-Isothermal Pipe Flow” interface. A theoretical validation is made by confrontation with analytical results. Then, using experimental results in multiple configurations, the model is adjusted to make it predictive.
Towards a Quantitative Prediction of Ice Forming at the Surface of Airport Runways
COMSOL European Conference 2017
J. D. Wheeler1, M. Rosa2, L. Capobianco2, P. Namy1
1. SIMTEC, 8 rue Duployé, Grenoble, 38100, France
2. Groupe ADP - Laboratoire DIAMLX, 16 rue du Miroir, Roissy Charles de Gaulle, 95931, France
Anticipation of meteorological events such as ice forming is a key challenge to optimize the use of deicing/anti-icing products on airport runways. To obtain a predictive numerical tool of ice forming on the runways, Groupe ADP and SIMTEC developed a COMSOL Multiphysics® model, in which several physical phenomena contributing to the surface temperature variations of the runway are involved. Radiative exchanges occur from and to the atmosphere together with the solar radiations. Moreover, the underground thermal inertia has a key role as it varies depending on the season and the runway temperature of the previous days. At last, the wind is also a source of thermal variation because of the convection. A comparison with temperature measurement on the runway provides an evaluation of the model abilities. Whereas some phenomena contribution precision should be improved, the computation results are in agreement with the experimental measurements. Thanks to the numerical model, the different thermal contributions are gathered and the variation of the temperature is computed over time at the surface and in the different layers of the runway foundation.
Optimization of an explosive mixture cooling process including a phase change
COMSOL European Conference 2017
J. D. Wheeler1, C. Coulouarn2, E.Benade2, P. Namy1
1. SIMTEC, 8 rue Duployé, Grenoble, 38100, France
2. Thales TDA, Thales, La Ferté-Saint-Aubin, 45240, France
In the scope of improvement of the industrial “ammunition cooling” process, a COMSOL Multiphysics® model is developed to transfer an existing cooling process. A shell body is filled with a liquid explosive mixture. When all the shells have been filled the “cooling phase” takes place using specific equipment. This explosive mixture undergoes a phase change during the cooling and the solidification enthalpy is introduced to the model thanks to the “modified heat capacity” method. The specific equipment allows for cooling shells from its bottom to its top and therefore to ensure a continuous and unique solidification front. While the air surrounding the top of the device is heated, the bottom of the device is either soaked in water or cooled via a high velocity air flow. Thanks to the modelling approach, the industrial transfer had been optimized, by minimising set parameters for cooling phase. A user-interface is developed to allow the users of the model to easily vary the cooling conditions and the shell body geometry. COMSOL Server™ enables a remote computing to the users, thanks to an https secured internet connexion.
Numerical modeling of flow focusing: Quantitative characterization of the flow regimes
Physics of Fluids 2017
V. Mamet1,2, P. Namy3, and J.-M. Dedulle1,3
1 Laboratoire des Materiaux et du Genie Physique (LMGP), Grenoble INP–CNRS, 38016 Grenoble, France
2 DBV Technologies, 92220 Bagneux, France
3 SIMTEC, 38100 Grenoble, France
Among droplet generation technologies, the flow focusing technique is a major process due to its control, stability, and reproducibility. In this process, one fluid (the continuous phase) interacts with another one (the dispersed phase) to create small droplets. Experimental assays in the literature on gas-liquid flow focusing have shown that different jet regimes can be obtained depending on the operating conditions. However, the underlying physical phenomena remain unclear, especially mechanical interactions between the fluids and the oscillation phenomenon of the liquid. In this paper, based on published studies, a numerical diphasic model has been developed to take into consideration the mechanical interaction between phases, using the Cahn-Hilliard method to monitor the interface. Depending on the liquid/gas inputs and the geometrical parameters, various regimes can be obtained, from a steady state regime to an unsteady one with liquid oscillation. In the dispersed phase, the model enables us to compute e evolution of fluid flow, both in space (size of the recirculation zone) and in time (period of oscillation). The transition between unsteady and stationary regimes is assessed in relation to liquid and gas dimensionless numbers, showing the existence of critical thresholds. This model successfully highlights, qualitatively and quantitatively, the influence of the geometry of the nozzle, in particular, its inner diameter.
Modeling of the Lithium Hydride Hydrolysis under Low Relative Humidity
International Journal of Hydrogen Energy 2017
A. Oury2, P. Namy2, JP Bellat3, E. Sciora3, R. Besnard1
1 CEA Valduc, 21120 Is sur Tille France
2 SIMTEC, 8 rue Duploye 38100 GRENOBLE France
3 Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS, Universite Bourgogne Franche-Comte, 9 A. Savary, BP47870, 21078 Dijon, France
A reactional mechanism describing the hydrolysis of lithium hydride (LiH) under moist atmosphere is proposed and modeled. It involves the formation of lithium oxide (Li2O) at low vapor pressure and both lithium oxide and lithium hydroxide (LiOH) at higher vapor pressures, with diffusion of water in these layers. A numerical model based on this mechanism is implemented with COMSOL Multiphysics to simulate the hydrolysis of LiH particles in open system (constant water vapor pressure). Kinetic parameters such as rate constant of reactions and diffusion coefficient of water in Li2O and LiOH are first fitted against experimental data. The best agreements are obtained when the diffusion coefficient of water is 10 times higher in LiOH than in Li2O. The resulting model accurately predicts the hydrolysis rates experimentally measured for a wide range of water vapor pressures (0.3e17 Pa). The hydrolysis mechanisms are compatible with a Li2O production limited by water diffusion and a LiOH production governed by the kinetics. Finally, simulation suggest that the thickness of the Li2O layer does not depends much on the water vapor pressure whereas that of LiOH increases drastically at high water vapor pressures.
Multiphysics Modeling of Pulsed Laser Welding
ICALEO 2016
V. Bruyere2, C. Touvrey1, P. Namy2 and N. Authier1
1CEA Valduc, 21120 Is sur Tille France
2SIMTEC, 8 rue Duploye 38100 GRENOBLE France
Laser beam welding is largely used in industrial manufacturing because of the advantages it provides, such as high-quality welds. Nevertheless, depending on the operating conditions, porosities or unwanted deformations can be produced during welding operations. In order to understand and control the responsible underlying mechanisms, numerical models are developed in a unique finite element formalism. All models are based on experimental characterizations. First of all, a thermal-hydraulic model is developed to predict the dimensions of the melted zones and the heataffected zones as well as the mechanisms of porosities formation for a Ti6VAl4 alloy. A thermal-mechanical model including metallurgical phase changes is then developed in order to predict the residual states of stress and strain. The heat source is calibrated with an optimization procedure based on thermal-hydraulic analysis. Indeed, an equivalent approach is used to reduce the computational time for thermal-mechanical computations. Finally, this model is applied to a study case and numerical results are discussed and compared with experimental data.
Implementation of an Interferometric Sensor for Measuring the Depth of a Capillary Laser Welding
ICALEO 2016
N. Authier1, A. Baptiste1, C. Touvrey1, V. Bruyere2, and P. Namy2
1CEA Valduc, 21120 Is sur Tille France
2SIMTEC, 8 rue Duploye 38100 GRENOBLE France
The welding laboratory located at the Commissariat a l'Energie Atomique et Aux Energies Alternatives (CEA) Valduc center in France uses pulsed and continuous wave (CW) laser sources to assemble metallic parts of low thicknesses. This article discusses the results obtained by the recent implementation of the In-process Depth Meter (IDM) of PRECITEC keyhole depth measurement sensor in our laboratory. This distance measurement technology uses a Michelson interferometer adapted to the very special conditions of the laser beam welding. Micrographs of pulsed welding tests on 316L stainless steel, TA6V plane sheets butt joints are analyzed and compared to the inline collected signals. The system's ability to follow dynamically the formation of the keyhole into the molten metal is evaluated and compared to numerical models performed in the lab using the nite element COMSOL Multiphysics software.
Electrical and Bubbly Flow Modeling of a Molten Salt Electrolysis Cell
COMSOL European Conference 2016
A.Oury1, P. Namy1, A.M. Martinez2, K.S. Osen2 and A. Solheim2
1SIMTEC, 8 rue Duploye 38100 GRENOBLE France
2SINTEF Materials and Chemistry, Sem Saelands vei 12, 7465 TRONDHEIM, Norway
A laboratory-scale electrolysis cell for the recovery of metals is simulated with COMSOL Multiphysics. Two models are implemented: an electrical model simulating the current density (reaction rate) distribution at the electrodes and a laminar bubbly flow model which solves for the electrolyte velocity induced by gas bubble production at the anode. A parametric study on the mesh refinement, the anode-cathode distance (ACD) as well as the bubble diameter (Db) is carried out. Quite heterogeneous current distributions are simulated at the electrodes’ surface, with strong edge effect at the cathode. At the anode, a more uniform current is however obtained when increasing ACD. The bubbly flow model suggests that significant electrolyte convective motions between the electrodes are favoured for small values of both ACD and Db.
Aerothermal Simulation of a Refrigerated Truck Under Open/Closed-Door Cycles
COMSOL European Conference 2015
A. Oury1, P. Namy1, M. Youbi-Idrissi2
1 SIMTEC, GRENOBLE
2 AIR LIQUIDE, Jouy en Josas, France
Heat transfer inside a refrigerated truck is a key phenomenon that governs the temperature inside the truck and the regulation of the cooling system. Up to now, a lot of experimental studies ([Tso et al., 02]) have been carried out to assess the effect of opening the door and to minimize the external heat transfer with fan air curtain. Together with AIR LIQUIDE, the world leader in gases, technologies and services for Industry and Health, SIMTEC, a French COMSOL certified consultant company, has developed a numerical model in COMSOL Multiphysics® software to simulate the heat transfer phenomena occurring during the use of the refrigerated truck, considering both open- and closed-door periods. The model is based on a coupling between CFD (k-ε/k-ω models) and heat transfer. Comparison with experimental results shows a reasonable agreement in terms of temperature inside the volume and at some specified points. This work demonstrates the feasibility of using COMSOL to model non-isothermal turbulent flow.
Numerical Characterizations of Viscoplastic Behavior of TA6V with Metallurgical Phase Change
COMSOL European Conference 2015
Vincent Bruyère 2, Charline TOUVREY1, Patrick NAMY2
1 CEA Valduc, 21120 Is sur Tille
2 SIMTEC, 38100 GRENOBLE
In order to predict the residual mechanical state of assemblies during pulsed laser welding, mechanical and metallurgical behaviors of the materials need to be precisely characterized. Based on experimental data and analyses, a numerical model is developed in Comsol Multiphysics to take into account the predominant effects (metallurgy influence, viscoplastic behavior) identified for TA6V. To validate our implementation, experimental and numerical results are compared at different temperatures.
A Phase Field Approach to Model Laser Power Control in Spot Laser Welding
COMSOL European Conference 2014
Vincent Bruyère 2, Charline TOUVREY1, Patrick NAMY2
1 CEA Valduc, 21120 Is sur Tille
2 SIMTEC, 38100 GRENOBLE
Spot laser welding is largely used in industrial manufacturing, especially in the case of small penetration depth. Unfortunately, welded joins are often polluted by porosities. The formation of porosities depends on complex thermo-hydraulic phenomena. To understand and control these mechanisms, the COMSOL Multiphysics software is used to model both the interaction and cooling stages of an isolated impact made with a Nd:YAG pulsed laser. The model is based on the Phase Field method in order to apprehend the evolution of the liquid-gas interface shape. The numerical results are compared to experimental characterizations for different operating conditions. At last, the benefic effect of the laser power control (pulse shaping) is demonstrated.
Thermohydraulic modeling of pulsed laser welding
ICALEO 2013
Vincent Bruyère 1, Charline TOUVREY1, Patrick NAMY2
1 CEA Valduc, 21120 Is sur Tille
2 SIMTEC, 38100 GRENOBLE
The major aim of this study is to increase our understanding of the link between operating parameters and thermo-hydraulic evolution in the welding area, in the case of an isolated impact made with a Nd:YAG pulsed laser on a thin Ti6Al4V sheet. Two numerical approaches are used to model both the interaction stage and the cooling one. During the interaction, the free surface behavior is precisely described by a moving mesh method (ALE method). The dependence between the interface temperature and the recoil pressure is discussed and a simplified approach is used. The keyhole collapse and the cooling stage are modeled by the phase field method (Eulerian method), which enables to consider the behavior of the gas trapped into the melting pool. Numerical calculations are compared to experimental characterizations (melted zone shape and defects position), in the case of relatively low laser power (inferior to 1000 W).
Comparison between Phase Field and ALE Methods to model the Keyhole Digging during Spot Laser Welding
COMSOL European Conference 2013
V. Bruyère1 , Charline TOUVREY1*, Patrick NAMY2
1 CEA DAM Valduc, 21120 Is sur Tille
2 SIMTEC, 38100 GRENOBLE
1*This email address is being protected from spambots. You need JavaScript enabled to view it.
Nowadays, spot laser welding is a full-fledged part of industrial manufacturing and is routinely used due to its advantages. It generates very located temperature gradients, and therefore, induces small distortions in the pieces. The COMSOL Multiphysics software is used to model the interaction stage of an isolated impact made with a Nd:YAG pulsed laser. The free surface evolution has been precisely described with a moving mesh method (ALE method) by imposing the recoil pressure and the energy deposition as boundary conditions. The results have been compared with those obtained with a fixed mesh method (Phase Field method) for isothermal and thermal cases. A discussion is proposed to choose the more appropriate method to model this problem.
Keywords: Welding, ND : YAG pulsed laser, Thermo-hydraulic, ALE, Phase-Field method.
Formation of Porosities During Spot Laser Welding of Tantalum
COMSOL European Conference 2011
C. Touvrey1 , and P. Namy2
1 CEA Valduc, Is-sur-Tille, France
2 SIMTEC, Grenoble, France
The aim of the study is to predict the formation of porosities in the case of spot laser welding of tantalum. During the interaction, a deep and narrow cavity, called the keyhole, is generated. At the end of the interaction, surface tension provokes the collapse of the keyhole. Gas bubble can then be trapped into the melting pool, and give birth to residual porosities, according to the solidification time.
A model has yet been developed to simulate keyhole collapse. This model was presented at the last COMSOL European conference. The purpose of the present study is to simulate the bubble up rise. The problem is especially complex due to the high surface tension of the liquid tantalum (2.1 N.m-1).
Comparison Between Honeycomb and Fin Heat Exchangers
COMSOL European Conference 2011
P. Gateau1 , P. Namy2 , and N. Huc3
1 SAS SYNGAS, Saint Viaud, France
2 SIMTEC, Grenoble, France
3 COMSOL, Grenoble, France
Metal honeycombs are used as catalyst supports. They can be considered as complex fins for heat exchange. A simple heat transfer model was compared with 2D simulations using COMSOL Multiphysics. There was a good correlation when the fluid temperature was the same in all cells. However, significant discrepancy apperared when compared with a 3D simulation with laminar flow.
Honeycomb cells produced a temperature gradient which reduced the heat transfer. The radiant transfer was also investigated using 2D simulation. Modeling using COMSOL revealed the drawbacks of using honeycombs in steam reforming reactors. 3D modeling showed that a careful representation of the inlet was needed for realistic results.
Finite Element Analysis of Cables Heating Due to PoE/PoE+
COMSOL European Conference 2010
S. Francois1, and P. Namy2
1Nexans Research Center, Lyon, France
2SIMTEC, Grenoble, France
Power over Ethernet (PoE/PoE+) is a technology allowing to transmit data and power over the same data cable. The major concern for this technology is the degradation of data transmission performances due to the temperature increase in the cable. To have a better quantitative and qualitative knowledge of the temperature field in the cables, Nexans has developed a 2D finite element thermal model thanks the software COMSOL Multiphysics. In this model, the heat source is due to the joule effect, depending on the intensity level. This thermal model enables us to take into consideration several configurations of cable bundles and to optimize the temperature field thanks to cable design.
Level Set Method for Fully Thermal-Mechanical Coupled Simulations of Filling in Injection and Micro-Injection Molding Process
COMSOL European Conference 2009
M. Moguedet1, R. Le Goff1, P. Namy2, and Y. Béreaux3
1Pôle Européen de Plasturgie, Bellignat, France
2SIMTEC, Grenoble, France
3INSA de Lyon, Site de Plasturgie, Bellignat, France
In this work we tackle a more theoretical aspect of micro-injection molding, to better understand physics during the process, through numerical simulations of cavity filling. We developed a two phase flow approach by the use of COMSOL Multiphysics®. In a first step, a Level Set model is applied to several configurations: Newtonian and non Newtonian fluid (Cross viscosity law), coupled with a thermal equation and a thermal dependence of the viscosity (Williams-Landel-Ferry law). We take into account the unsteady thermal behavior of the mould while injecting the polymer into the cavity. Finally, as air –trapping often occurs in the injection molding process, we present some results considering a pseudocompression law (low Mach number) for the air. To conclude, we show the ability of the COMSOL model to simulate polymer filling in microfeatures.
On the Use of COMSOL Multiphysics to Understand and Optimize the Filling Phase in the Injection and Micro-Injection Molding Process
COMSOL European Conference 2007
M. Moguedet1, P. Namy2, and Y. Béreaux3
1Pôle Européen de Plasturgie, Bellignat, France
2SIMTEC, Grenoble, France
3LAMCOS, Site de Plasturgie, INSA Lyon, Bellignat, France
The work presented here deals with the simulation of the cavity filling stage of the injection and micro-injection molding process for thermoplastic materials. COMSOL Multiphysics gives us the means to take into consideration some other aspects usually neglected in commercial 3D softwares dedicated to polymer processing. In particular, tracking of the flow front is based on a Level Set approach. Results are presented for a Newtonian and non-Newtonian polymer, and in an isothermal or thermal dependant configuration. The calculations are compared to experimental results on a polypropylene.
Convective Movements in an Electrolyser
COMSOL European Conference 2007
B. Morel1, P. Namy2, C. Belhomme1, and I. Crassous3
1Comurhex, Pierrelatte, France
2SIMTEC, Grenoble, France
3LI2C, Paris, France
Modeling electrolysers is a challenge because of the strong coupling between electrical, thermal and CFD equations. Indeed the electrical conductivity of the electrolyte varies with the temperature, which in turn depends on the heat dissipated by the Joule effect and anode over-voltage.In the present study, the fluid velocity values are computed near the electrodes using a diphasic level set model, but the full calculations are performed using a monophasic model. Our goal is to evaluate the relationship between the average temperature of the cell and the average current for a given cooling surface.
