3D Multiphysics Simulation Research Articles

Investigation on electromagnetic and heat transfer coupling of heating susceptor for selective microwave hybrid soldering: 3D multi-physics simulation and experiment

The utilization of microwave hybrid heating as an emerging technique in the field of low-temperature joining presents a notable benefit of delivering both selective and rapid heating, a feature that is not commonly observed in traditional soldering methods. However, due to the complex multi-physical coupling problem, the factors and mechanisms affecting the heating effect of the susceptors have not been clearly explained. To examine the effect of susceptor shape, size, and process parameters on heating efficiency, a numerical model of electromagnetic and thermal coupling was created to analyze silicon carbide susceptor heating under microwave action. The response surface method examined how microwave frequency, power, and exposure time affect susceptor heating efficiency. The model’s three process parameters are used to selectively heat Cu/SAC305/Cu joints, and the connection mechanism is studied. The results reveal that cylindrical susceptors heat more efficiently and uniformly than cubic ones. The heating efficiency is the highest when the height of the susceptor is 30 mm. Moreover, the heating effect is optimum at 2.45 GHz. Microwave power and exposure period positively linked with susceptor heating efficiency. The finite element simulation model shows that energy consumption at 2.45 GHz\\2 kW210 s is 78.38 % of that at 2.45 GHZ\\1 kW370 s, and the maximum temperature difference is 73.44 % of that at 2.45 GHz\\3k W\\90 s. MHS experiments show that as exposure duration increases, Cu6Sn5 grew and the growth orientation becomes consistent and perpendicular to the {0 0 0 1} family of crystal planes. Under process settings of 2.45 GHz \\ 2 kW \\ 210 s, the joint can achieve 16.55 MPa shear tensile strength. The results can serve as references for the study on selective microwave hybrid soldering and provide a new idea for selective and efficient soldering.

Multiscale multiphysics modeling of ammonia-fueled solid oxide fuel cell: Effects of temperature and pre-cracking on reliability and performance of stack and system

Ammonia is a promising carbon-free fuel for solid oxide fuel cells (SOFCs). However, direct feeding of ammonia into the SOFC may lead to serious degradation due to the nitriding. Conversely, the pre-cracking of ammonia introduces complexity to the system design and causes increased power losses in the system. Therefore, it is crucial to explore all these aspects simultaneously. In this context, this study introduces a novel multiscale modeling approach by integrating a 3D multiphysics simulation of the ammonia-fueled SOFC stack with system-level modeling to investigate the reliability and performance of the stack and system. Two different cell technologies developed for low temperature (LT) and high temperature (HT) operation are investigated at LT (600 – 700°C) and HT (700 – 800°C) ranges. The results indicate that fuel inlet temperature should be 55°C and 18°C higher than the minimum temperature in 0% pre-cracking case for HT and LT cases, respectively. The increase in the required air flow rate for cooling in the 100% pre-cracking case compared to the 0% pre-cracking case is around 100% and 216% for the HT and LT cases, respectively. However, stack power production and power losses in the system components are comparable for LT and HT cases which leads to similar system performance. A larger share of the active area is affected by nitriding in LT cases than HT ones. However, a smaller cracking ratio at LT (∼ 82%) compared to HT conditions (∼ 92%) is needed for elimination of nitriding. While the LT and HT cases are comparable in terms of system power production, the lower stack outlet temperatures in LT cases require novel and more expensive catalysts for ammonia pre-cracking and HT cases need more expensive steels.

3D Simulation-Driven Design of a Microfluidic Immunosensor for Real-Time Monitoring of Sweat Biomarkers.

This study presents the design and comprehensive 3D multiphysics simulation of a novel microfluidic immunosensor for non-invasive, real-time detection of pro-inflammatory biomarkers in human sweat. The patch-like device integrates magnetofluidic manipulation of antibody-functionalized magnetic nanoparticles (MNPs) with direct-field capacitive sensing (DF-CS). This unique combination enhances sensitivity, reduces parasitic capacitance, and enables a more compact design compared to traditional fringing-field approaches. A comprehensive 3D multiphysics simulation of the device, performed using COMSOL Multiphysics, demonstrates its operating principle by analyzing the sensor's response to changes in the dielectric properties of the medium due to the presence of magnetic nanoparticles. The simulation reveals a sensitivity of 42.48% at 85% MNP occupancy within the detection zone, highlighting the sensor's ability to detect variations in MNP concentration, and thus indirectly infer biomarker levels, with high precision. This innovative integration of magnetofluidic manipulation and DF-CS offers a promising new paradigm for continuous, non-invasive health monitoring, with potential applications in point-of-care diagnostics, personalized medicine, and preventive healthcare.

A thermal fluid dynamic model for the melt region during the laser powder bed fusion of polyamide 11 (PA11)

Studying the physical characteristics of the melt region in polymer-based laser powder bed fusion (PBF-LB/P) offers good comprehension that is essential for quality control, process optimization, understanding of material behavior, and preserving process consistency. Among the few numerical modelling investigations of PBF-LB/P, this study focuses on 3D multiphysics simulation of melt pool morphologies, beginning with powder bed preparation incorporating the actual particle size distribution using the discrete element method (DEM). A thermal fluid dynamic numerical model is then developed based on the finite volume method (FVM) using Flow-3D Weld to simulate PBF-LB while using polyamide 11 (PA11) as the primary material. The cooling after sintering plays a crucial role for the formation of the melt region due to the high viscosity of the polymer material effectively resulting in creeping flow. Here, we propose a model for both sintering as well as the subsequent cooling step, a two-step model capable of simulating the finished structure accurately with relatively low computational resources. The model's accuracy is verified through a mesh dependency analysis and its predictive power via validation against internal single-track experiments providing dimension data on the melt region width and depth. The simulation results allow for a detailed exploration of the effects of laser settings on melt region morphologies and the occurrence of defects. The model's scope is further extended to multi-track simulation, revealing the connection between surface roughness and laser settings. In general, this study provides significant contributions to the comprehension of PBF-LB/P methodologies which in turn can be used for further process improvement.

Susceptor based design strategies for enhancing microwave hybrid heating capability via experimental analysis, 3D multi-physics simulation and parametric optimization

Microwave processing has gained remarkable recognition based upon volumetric processing that is energy efficient. Susceptor-assisted microwave heating is a fast-emerging technology because of its advantages over traditional microwave processing. Susceptor help to speed up microwave processing by offering two-way heating with less heat loss from the material's surface. The present investigation brings out ways (theoretical, simulation and experimental) to select appropriate susceptor material by considering different types of microwaves absorbing material (alumina, yttria stabilized zirconia, boron nitride and silicon carbide) for efficient microwave heating. Theoretical analysis (dielectric properties, penetration depth, absorption loss and reflection loss) suggests silicon carbide (SiC) to be the most suitable susceptor. COMSOL Multiphysics based simulation in conjunction with experimental results were utilized for critical understanding of SiC susceptor heating. The influence of physical parameters: microwave input power, microwave frequency, placement of susceptor inside cavity and dimension of susceptor on electric field distribution and temperature profile of SiC susceptor are also investigated and presented in detail. Among all susceptor materials, SiC exhibited highest heating rate in similar operating parameters. The temperature obtained for SiC susceptor during microwave heating without casket (80 °C) was significantly lower than that with casket insulation (1003 °C). A susceptor of 10 mm thickness with cross-section of 625 mm2 was found to be the optimum dimension for SiC susceptor. The maximum temperature obtained by the SiC susceptor was 658 °C, 1003 °C, 1182 °C and 1380 °C for input power of 800 W, 1200 W, 1600 W and 2000 W respectively. Simulation data were validated with experimental results. The results exhibit a good agreement between simulation results and experimental data.

3D Multiphysics simulation of microwave heating of bulk metals with parametric variations

Microwave processing of metal base material is a novel and energy-efficient technique. Microwave heating of bulk metal is an emerging method with cost, time, and energy savings over conventional heating methods. This numerical study uses the finite element method-based COMSOL Multiphysics tool to analyse the microwave heating properties of a bulk metal sample. Further in this study, the effects of tooling design assembly and microwave power parameters have been analysed for temperature profile and electric field distribution. The outcome of parametric variations has been analysed in terms of electric field distribution, heating uniformity, temperature gradient, and energy requirement. Experimental results coincided with simulated results in terms of time-temperature characteristics within ±5% error. The heating uniformity of bulk metal can be achieved at low power with small-size component whereas high power creates thermal heterogeneity with high energy consumption. The cylindrical casket geometry shows uniform field distribution with rapid heating of the specimen compared to prismatic geometry. Susceptor's dielectric properties have a significant effect on the homogeneity of the process, and the heating efficiency of the irradiated specimen. The present simulation model can be used to control the heating rate of bulk metal considering various dynamic parametric properties for a complex microwave hybrid heating process.

Numerical Analysis on Temperature Distribution in a Single Cell of PEFC Operated at Higher Temperature by1D Heat Transfer Model and 3D Multi-Physics Simulation Model

Numerical Analysis on Temperature Distribution in a Single Cell of PEFC Operated at Higher Temperature by1D Heat Transfer Model and 3D Multi-Physics Simulation Model

Virtual cloud computing–based and 3D multi-physics simulation for local oxygen starvation in PEM fuel cell

In this paper, the effects of load and air-flow change on a serpentine multi-channel proton-exchange membrane fuel cell (PEMFC) were studied through numerical simulation and cloud computing technology. For this purpose, load change, air-flow change pattern and initial value, as well as its lag time to the load change, were considered. The transient response of local oxygen distribution to load change and flow change was investigated, and the local oxygen starvation (LOS) behavior observed. Detailed results are presented to show the transient response of the cell in terms of average oxygen concentration and water content distribution. This work shows that the local oxygen starvation process depends on factors such as load changes and air-flow rate of change, which can be alleviated or eliminated by adjusting air flow and pattern. It is also shown that simulation efficiency can be improved by cloud computing technology. Finally, the validity of the numerical model proposed in this paper is verified by the comparison between the model results and experimental data.

Structure-improved current collector for performance enhancement of electrolyte membrane dehumidifiers: 3D simulations and in-situ measurements

Electro-dehumidification based on proton exchange membrane (PEM) is promising owing to its compact assembly and convenient operation. By numerically improving the effects of current collectors’ structure on the operation performance (moisture removal rate, current/temperature/humidity distribution and energy utilization rate), this research achieved a significant dehumidification enhancement (more than 40%) for electrolyte membrane dehumidifiers. 3D Multiphysics simulation and in-situ verification measurements were conducted. Compared with the original collectors, the dehumidification rate can be enhanced by 35% with the “口” collectors, and by more than 40% with “X”, “#” and “▪” collectors. The best performance occurred with the anode collector of “▪” structure (opening area: 9 × 10-4 m2), which the rate increased by 46%. The improvement effects were mainly due to the improvement of potential distribution (especially on the anode side) and the concentration of the reactant (water vapor) reaching the catalyst interface. Compared with the “口” type, the current density uniformity of membrane dehumidifier with the “▪” collector increased from 0.0033 to 0.032. The temperature and moisture distribution were also more uniform. The opening structure of anode collector resulted in a more significant effect than the opening area. Therefore, the system energy utilization rate and COP (coefficient of performance) can be doubled, up to 3.48 × 10−2 g·J−1·m−2 and 0.26, respectively. This research provides a theoretical basis and practical direction for improving current collectors of PEM dehumidifiers.

Construction and Simulation of a Planar Transformer Prototype

This paper illustrates the design and building of a planar transformer prototype with a 1:1 transformation ratio for high-frequency applications in power electronics. By using reference literature and considering the ferrite core dimensions, the windings were conceived and exported to Gerber format using PCB design software. The transformer prototype was then assembled and tested under laboratory conditions for frequencies from 800 Hz to 5 MHz, which showed a sinusoidal wave at the transformer output from 1.3 kHz onwards and a better performance starting at 10 kHz, where the loses were significantly reduced and the transformation ratio was closer to the originally designed. As a final step, a finite element method (FEM) análisis was carried out to understand the electromagnetic flux behavior using a 3D Multiphysics simulation software. The 3d building process and details are explained step by step and the resulting magnetic flux density is graphically shown for the core and the windings.

Self-driven liquid metal cooling connector for direct current high power charging to electric vehicle

Direct current-based high power charging (DC-HPC) technology is expected to shorten the charging time of electric vehicles (EV) significantly and lessen the range anxiety. However, a high charging current would cause a remarkable temperature rise of the charging connector due to the Joule heat, which must be adequately removed to keep its durability and safety. This paper reported a novel concept of the self-driven liquid metal (LM) cooling connector (LMCC) used for DC-HPC. The room-temperature LM of Galinstan filled in the flexible tube is applied as the current-carrying conductor and circulated-cooling fluid simultaneously. The circulation-flow LM is driven by the designed electromagnetic force through coupling the charging current and magnetic field from a pair of permanent magnets, which does not need additional pumping devices. A principle experiment is conducted to demonstrate the driving and cooling performances of LMCC, which shows excellent circulation flow rate (with the flow rate of 0.75 L/min and the driven pressure head of 44.7 kPa) of the LM in the flexible tube (diameter of 6 mm and length of 2.65 m) and only achieves a temperature rise of about 13 °[email protected] Both 3D multi-physics simulation and theoretical models are also established and demonstrated by experiment results to accurately evaluate the impacts of the charging current, magnetic field, and flexible tube size on the performance of self-driven LMCC. The results indicate that increasing the diameter of the flexible tube could significantly reduce its temperature rise induced by a high charging current and does not affect its flexibility. A super-low temperature rise of 10.6 °[email protected] for the charging cable (the diameter of 10 mm and length of 3 m) is designed. This work provides a new strategy for the heat dissipation technology of DC-HPC charging connectors.

Rapid modeling of borehole measurements of nuclear magnetic resonance via spatial sensitivity functions

Borehole measurements of nuclear magnetic resonance (NMR) are routinely used to estimate in situ rock and fluid properties. Conventional NMR interpretation methods often neglect bed-boundary and layer-thickness effects in the calculation of fluid volumetric concentrations and NMR relaxation-diffusion correlations. Such effects introduce notable spatial averaging of intrinsic rock and fluid properties across thinly bedded formations or in the vicinity of boundaries between layers exhibiting large property contrasts. Forward modeling and inversion methods can mitigate the aforementioned effects and improve the accuracy of true layer properties in the presence of mud-filtrate invasion and borehole environmental effects across spatially complex formations. We have developed a fast and accurate algorithm to simulate borehole NMR measurements using the concept of spatial sensitivity functions (SSFs) that honor NMR physics and incorporate tool, borehole, and formation geometry. Tool sensitivity maps are derived from a 3D multiphysics forward model that couples NMR tool properties, magnetization evolution, and electromagnetic propagation. In addition, a multifluid relaxation model based on Brownstein-Tarr’s equation is introduced to estimate layer NMR porosity decays and relaxation-diffusion correlations from pore-size-dependent rock and fluid properties. The latter model is convolved with the SSFs to reproduce borehole NMR measurements. The results indicate that NMR spatial sensitivity is controlled by porosity, electrical conductivity, excitation pulse duration, and tool geometry. We benchmark and verify the SSF-derived forward approximation against 3D multiphysics simulations for a series of synthetic cases with variable bed thickness and petrophysical properties, and in the presence of mud-filtrate invasion in a vertical well. Results indicate that the approximation can be executed in a few seconds in a central processing unit, by a factor of 1000 times faster than rigorous multiphysics calculations, with maximum root-mean-square errors of 1%.

Cutting-fluid flow with chip evacuation during deep-hole drilling with twist drills

In this study the important aspects of cutting fluid distribution and the chip evacuation during micro twist deep-hole drilling are investigated using 3D multi-physics simulation methods. A coupled particle simulation is performed to analyze the chip transport by combining Smoothed Particle Hydrodynamics and the Discrete Element Method. Therefore, the transient transport of the chips is compared to a simulation scenario without chips. The coupled particle approach is capable to deal with free surfaces and fluid–solid interactions, that are subject to major topological changes over time. The chip positions resulting from the coupled particle simulation are used to carry out a Computational Fluid Dynamics simulation which considers the physical boundary conditions of the fluid and the process parameters to perform in-depth flow analyses. The results show good qualitative agreement between both simulation methods. Furthermore, the results show that large dead-zones with no fluid or almost zero fluid velocity exist in the flutes and that the chips there only experience a small evacuation force from the cutting fluid. The presented coupled approach of combining CFD and SPH–DEM simulation provide a significant support for future investigations to research the chip transport and to improve the tools and the process further.

3D multiphysic simulations of energy field and material process in radial ultrasonic rolling electrochemical micromachining

The radial ultrasonic rolling electrochemical micromachining (RUR-EMM) combined rolling electrochemical micromachining (R-EMM) and ultrasonic vibration was studied in this paper. The fundamental understanding of the machining process especially the interaction between multiphysics in the interelectrode gap (IEG) was investigated and discussed by the finite element method. The multiphysics coupling model including flow field model, Joule heating model, material dissolution model and vibration model was built. 3D multiphysics simulation based on micro dimples process in RUR-EMM and R-EMM was proposed. Simulation results showed that the electrolyte flowed into and out IEG periodically, gas bubbles were easy to squeeze out and the gas void fraction deceased about 16% to 54%, the maximum current density increased by 1.36 times in RUR-EMM than in R-EMM in one vibration period of time. And application of the ultrasonic vibration increased the electrolyte temperature about 1.3–4.4% in IEG. Verification experiments of the micro dimple process denoted better corrosion consistency of array dimples in RUR-EMM, there was no island at the micro dimple bottom which always formed in R-EMM, and an aggregated deviation of less than 8.7% for the micro dimple depth and 4% for the material removal amount between theory and experiment was obtained.

Visualisation and numerical analysis of laser powder bed fusion under cross-flow

As well as preventing oxidation, a cross-flow of inert gas over the powder bed extracts process by-products, making it critical for process repeatability and build quality during the additive manufacturing of metallic parts. In this study, high-magnification schlieren imaging was employed to visualise the interactions between the cross-flow, laser plume and individual powder particles for the first time. Novel 3D multiphysics simulations of the cross-flow, including the vapour jet and laser plume, were used to calculate energy, momentum and species transport over the processed area in order to understand and quantify the observed interactions. During processing, metallic fumes as well as a significant number of airborne powder particles and agglomerates were observed to remain close to the powder bed, over the scanned area. These particles interact in a range of stochastic collisions that affect the build consistency. Refractive index gradients were formed in the atmosphere above the island scans, which extended many tens of mm beyond the processing area. The rate of extraction of these by-products, regulated by the velocity of the cross-flow, was related to the quality of the builds. A cross-flow perpendicular to the laser scan direction was observed to remove airborne particles from adjacent laser scans most effectively, limiting laser-particle and particle-particle interactions. The model demonstrated that the refractive index gradients away from the vapour jet are due to the metal concentration rather than the temperature of the heated gas.

Magnetic field edge-effect affecting joint macro-morphology in sheet electromagnetic pulse welding

ABSTRACT Electromagnetic pulse welding (EMPW) is an environmentally friendly and advanced manufacturing technology. Researches find the macro-morphology of EMPW joint of sheets presents a multilayer ellipse. The EMPW experiments of Al-Cu sheets and Al-Mg sheets were carried out, both the macro-morphology and the micro-morphology showed there were collision zone, bonding zone and bonding affecting zone in the joint, presenting multilayer elliptical morphology, which was independent of material. The welded seam was in the bonding zone. The 3D multiphysics simulation results also showed that the distribution of the plastic deformation of Al sheet, Lorentz force, induced eddy current and magnetic flux density at the welded joint were all elliptical, and they presented a multilayer elliptical continuous equivalent distribution surface due to the difference of amplitude. The magnetic field edge-effect affects the distribution of the magnetic flux density, and the non-uniform distribution produces the multilayer elliptical macro-morphology, which causes the induced eddy current, Lorentz force and the deformed area of the aluminum alloy plate to be the elliptical shape. Therefore, the macro-morphology of EMPW joint of sheets is a multilayer ellipse. This work may provide theoretical support for the performance improvement of the EMPW technology.

3D Multiphysics Simulation of Jet Electrochemical Machining of Intersecting Line Removals

Jet electrochemical machining (Jet-ECM) is a non-conventional machining technology based on anodic metal dissolution. Jet-ECM utilizes a free-surface electrolyte jet to localize material removal. In this study Jet-ECM of intersecting line removals is investigated by help of experiments and simulation. The machining process is simulated with a 3D Finite Volume model considering the stratified two-phase flow of electrolyte and air. Furthermore, electrodynamics is modeled in terms of primary current distribution, and material removal is regarded transiently via geometry deformation according to Faraday’s law. The results reveal why an asymmetrical current profile occurs in Jet-ECM of intersecting line removals.

Multiphysics simulation of pulsed cold plasma arc rotation for enhanced hydrogen harvesting

Pulsed cold plasma reforming is a novel method to harvest hydrogen from hydrocarbons. The harvested hydrogen can feed a fuel cell for distributed generation of electricity in a stationary or mobile platform. The cold plasma arc is generated by a pulsating high voltage waveform. The arc rotates in the magnetic field caused by a ring permanent magnet, thus increasing the collision area between the arc and the fuel. Due to the difficulties of measurement of plasma properties such as ion and electron temperature without disturbing the plasma, multiphysics simulation is a key step in the design of electrodes, thereby increasing the hydrogen harvest rate in the syngas. In this paper, a 3D multiphysics simulation including fluid dynamics, thermal response, and electromagnetic fields has been carried out to assist in selection of the permanent magnet. Experiments were carried out to verify the simulation results. The 3D multiphysics simulation is demonstrated to be an effective tool to assist in the design of the reformer. The hydrogen harvest rate has been improved from 58.7% to 67.8% with the introduction of the magnet.

Development of Miniature Camera Module Integrated With Solid Tunable Lens Driven by MEMS-Thermal Actuator

The design, fabrication, assembly, and characterization of a miniature adjustable-focus camera module driven by MEMS-thermal actuators are presented. The camera module consists of one solid tunable lens for optical power variation, two identical MEMS-thermal actuators integrated with displacement amplifiers for lens element driving, a CMOS image sensor for recording, and necessary CNC fabricated components for supporting and housing. Fully 3D-multiphysics simulations with valid material properties are performed to explore the design and, hence, optimize the performance of the system. In this paper, the fabricated MEMS-devices are clearly demonstrated, and followed by the detailed characterization of the camera module. Static characterizations of the system, including the temperature distribution on actuators, electric resistance change with temperature increase, displacement-voltage curve of actuator, and the focal length tuning capability, are tested. Dynamic response speed and imaging performance of the camera module are also covered. Results show that the designed MEMS actuator is able to provide a maximum output displacement of 135 μm when a 10 V driving voltage is applied. Driven by the thermal actuator, the solid tunable lens presents a repeatable focal length tuning from 9.2 to 7.9 mm with precise focus control. The adjustable-focus capability of the miniature camera module is experimentally demonstrated by clearly focusing targets placed at different object distances.

General Regulation of Air Flow Distribution Characteristics within Planar Solid Oxide Fuel Cell Stacks

For solid oxide fuel cell (SOFC) stacks with a planar design, different structural designs were found to cause very different distribution trends of air flow rates fed to the piled cell units. Many implied optimization guidelines, which were independent of the specific structures, were achieved and verified by extensive 3D multiphysics simulations of the large-scale air flow path models. These conclusions could be very helpful for providing generality in practical structural design and parameter choice for planar SOFC stacks.