Multiphysics Numerical Model Research Articles

A fundamental investigation of thermo-capillarity in laser powder bed fusion of metals and alloys

Several different interfacial forces affect the free surface of liquid metals during metal additive manufacturing processes. One of these is thermo-capillarity or the so-called Marangoni effect. In this work, a novel framework is introduced for unraveling the effects of thermo-capillarity on the melt pool morphology/size and its thermo-fluid conditions during the Laser Powder Bed Fusion (L-PBF) process. In this respect, a multi-physics numerical model is developed based on the commercial software package Flow-3D. The model is verified and validated via mesh-independency analysis and by comparison of the predicted melt pool profile with those from lab-scale single-track experiments. Two sets of parametric studies are carried out to find the role of both positive and inverse thermo-capillarity on the melt pool shape and its thermal and fluid dynamics conditions. The thermo-fluid conditions of the melt pool are further investigated using appropriate dimensionless numbers. The results show that for the higher Marangoni number cases, the melt pool temperature drops, and at the same time, the temperature field becomes more uniform. Also, it is shown that at higher Marangoni numbers, temperature gradients decrease, thus reducing the role of conduction in the heat transfer from the melt pool. Furthermore, for the first time, a novel methodology is introduced for the calculation of the melt pool's average Nusselt number. The average Nusselt numbers calculated for the positive and inverse thermo-capillarity are then used for finding the effective liquid conductivity required for a computationally cheaper pure heat conduction simulation. The results show that the deviation between the average melt pool temperature, using the pure conduction model with effective conductivity, and the one obtained from the advanced fluid dynamics model is less than 2%.

Multiphysics and Multiobjective Design Optimization of High-Frequency Transformers for Solid-State Transformer Applications

This article proposes a multiphysics-based and multiobjective design optimization of high-frequency transformers (HFT) for solid-state transformer (SST) applications. Achieving an efficient SST, regardless of its topology, highly depends on the design optimization of its HFT design parameters. Also, a high-power-density. The proposed algorithm (based on time-harmonic electromagnetic, thermal, and fluid physics model coupling) minimizes the volume of the HFT, total cost as well maximizes its efficiency. A case study of $20 \text{ kW}$ , $10 \text{ kHz}$ is investigated and its Pareto optimal solutions (POS) presented. The simulation results show the various dependencies of the design variables on the proposed objective functions which verifies effectiveness of the proposed algorithm. The Pareto optimal solutions (POSs) show that efficiencies above $99\%$ can be achieved with appropriate selection of the design variables. From the POS, two case studies of the HFTs (referred to as $HFT_1$ and $HFT_2$ using $AMCC-100$ and $AMCC-250$ amorphous cores, respectively) are further investigated based on multiphysics numerical models. An experimental implementation of the optimized HFTs ( $HFT_1$ and $HFT_2$ ) is integrated with a self-tuned dual active bridge converter to validate their performance. The experimental measurements from the HFTs are in very good agreement with the optimization results.

Performing an Indirect Coupled Numerical Simulation for Capacitor Discharge Welding of Aluminium Components

Capacitor discharge welding (CDW) for projection welding provides very high current pulses in extremely short welding times. This requires a quick follow up behaviour of the electrodes during the softening of the projection. The possibilities of experimental process investigations are strongly limited because of the covered contact zone and short process times. The Finite Element Method (FEM) allows highly resoluted analyses in time and space and is therefore a suitable tool for process characterization and optimization. To utilize this mean of optimization, an indirect multiphysical numerical model has been developed in Ansys Mechanical APDL. This model couples the physical environments of thermal–electric with structural analysis. It can master the complexity of large deformations, short current rise times and high temperature gradients. A typical ring projection has been chosen as the joining task. The selected aluminium alloys are EN-AW-6082 (ring projection) and EN-AW-5083 (sheet metal). This paper presents the investigated material data, the model design and the methodology for an indirect coupling of the thermal–electric with the structural physic. The electrical contact resistance is adapted to the measured voltage in the experiment. The limits of the model in Ansys Mechanical APDL are due to large mesh deformation and decreasing element stiffness. Further modelling possibilities, which can handle the limits, are described.

Effect of processing parameters during the laser beam melting of Inconel 738: Comparison between simulated and experimental melt pool shape

Abstract Numerical simulation is a powerful tool to understand the link between processing parameters and solidification conditions during the laser beam melting (LBM) process. To be able to use this tool for microstructural control, numerical models need to be validated on a large set of experimental conditions, to ensure that the model describes the predominant physical phenomena. In this study, an experimental set of twenty tracks was produced in an Inconel 738 alloy, with a wide range of energy input and scanning speed. Experimental melt pool shapes were compared to the predictions of a multiphysics numerical model. In this model, the powder bed is considered as a continuum. The laser source is modeled with a Beer-Lambert absorption law, and surface tension, Marangoni force and recoil pressure are the driving forces for melt pool dynamics. This kind of model offers an efficient computational time, but requires a calibration of the absorption coefficient and a representative description of laser-matter interaction. In order to represent correctly heat and mass transfer during laser-matter interaction, the model needs to account for the loss of matter caused by the ejection of powder particles and spatters. A novel calibration method was proposed to calculate the absorption coefficient. This method uses the experimental cross sections of the melt pools and a simplified analytical expression of energy balance. The use of this calibration method enabled a good agreement between experiments and calculations on a large process window. The values obtained by the calibrations resulted in a phenomenological expression of absorptivity coefficient with process parameters. Based on this expression, a comparison was made with another numerical model from literature using a time-consuming ray-tracing method in order to calculate the absorptivity coefficient. Similar results have been obtained, demonstrating the potential of the proposed approach to predict the melt pool shape and thus better understand the combined effect of laser-matter interaction and solidification in LBM process.

Development of multi-physics numerical simulation model to investigate thermo-mechanical fatigue crack propagation in an autofrettaged gun barrel

In this research, a detailed multi-physics study has been carried out by numerically simulating a solid fractured gun barrel for 20 thermo-mechanical cycles. The numerical model is based on thermal effects, mechanical stress fields and fatigue crack mechanics. Elastic-plastic material data of modified AISI 4340 at temperatures ranging from 25 to 1200 °C and at strain rates of 4, 16, 32 and 48 s−1 was acquired from high-temperature compression tests. This was used as material property data in the simulation model. The boundary conditions applied are kept similar to the working gun barrel during continuous firing. A methodology has been provided to define thermo-mechanically active surface-to-surface type interface between the crack faces for a better approximation of stresses at the crack tip. Comparison of results from non-autofrettaged and autofrettaged simulation models provide useful information about the evolution of strains and stresses in the barrel at different points under combined thermo-mechanical loading cycles in both cases. The effect of thermal fatigue under already induced compressive yield due to autofrettage and the progressive degradation of the accumulated stresses due to thermo-mechanical cyclic loads on the internal surface of the gun barrel (mimicking the continuous firing scenario) has been analyzed. Comparison between energy release rate at tips of varying crack lengths due to cyclic thermo-mechanical loading in the non-autofrettaged and autofrettaged gun has been carried out.

Additively manufactured integrated slit mask for laser ultrasonic guided wave inspection

Guided ultrasonic waves are attractive for inspection of additively manufactured plate-like components. Illumination of a slit mask by a pulsed laser is one method by which guided ultrasonic waves can be generated. This work proposes a method for generating narrowband ultrasonic guided waves using an additively manufactured slit mask that is integrated onto the component during selective laser melting (SLM) process. Multiple guided wave modes with a dominant wavelength but with different frequencies were generated using the slit mask fabricated using AlSi12 material. The generated modes were identified using the time frequency response of the received signals and dispersion plots. Identifying the modes and its characteristics (frequency, wavelength, phase and group velocity) beforehand facilitates material and defect characterization. A multiphysics numerical model was developed to simulate laser generation of ultrasound and the model was validated using experimental results. The numerical model developed aided in understanding the physics of line arrayed laser ultrasonic generation and was used as a tool to optimize laser parameters. The developed model was used to study the effect of pulse width of the laser on Lamb wave mode generation. It was observed that a pulse width of 100 ns reduced the overall ultrasonic bandwidth to 4.5 MHz thereby limiting the modes to the fundamental modes A0 and S0 for the given wavelength of 0.8 mm. Rayleigh wave studies using a slit mask showed that the rate of decay of the fundamental frequency component was steeper than the rate of decay of the second harmonic component.

A 6M digital twin for modeling and simulation in subsurface reservoirs

A 6M digital twin for modeling and simulation in subsurface reservoirs

Three-dimensional thermohydrodynamic investigation on the micro-groove textures in the main bearing of internal combustion engine for tribological performances

A three-dimensional thermohydrodynamic numerical simulation study was used to investigate the impact of the micro-groove surface texturing on the tribological performances in the main bearing of the internal combustion engine. For this purpose, various number of grooves and groove height to the bearing surface were applied to determine the optimal texture surface parameters by comparing the load-carrying capacity and friction force in the engine main bearing. In the multiphysics numerical model, the three-dimensional Navier–Stokes equation was employed considering the cavitation mechanism based on the Elrod method in the solution. Using the transverse grooves on the bearing surface altered the cavitation response and film reformation. To validate the use of the current numerical model for analyzing the bearings, the obtained results were compared with those of the published theoretical papers, where a good agreement was obtained. The bearing performance was studied in thermal interface conditions to find the optimal set textures parameters that gave minimum fiction force with minimum loss in load-carrying capacity. The bearing with the optimal micro-groove texture parameter showed a reduction in friction (around 16%) with the minimum reduction in load-carrying capacity (around 6%) and the maximum reduction of the flow work (around 15%) compared with the untextured bearing surface. This paper focuses on the thermohydrodynamic investigation with a combination of thermal effects of the fluid film in the textured bearing. Meanwhile, the heat transfer characteristic, temperature distribution of solid bodies, and convection heat transfer coefficient in the contact surfaces of the textured bearing were investigated. The proposed multiphysics numerical model can be widely used for predicting the optimal texture surface parameters in different engineering systems modeling. Moreover, using the three-dimensional-based numerical model is more cost-effective compared with the experimental evaluation of the textured surface.

Modeling, design, and machine learning-based framework for optimal injectability of microparticle-based drug formulations.

Inefficient injection of microparticles through conventional hypodermic needles can impose serious challenges on clinical translation of biopharmaceutical drugs and microparticle-based drug formulations. This study aims to determine the important factors affecting microparticle injectability and establish a predictive framework using computational fluid dynamics, design of experiments, and machine learning. A numerical multiphysics model was developed to examine microparticle flow and needle blockage in a syringe-needle system. Using experimental data, a simple empirical mathematical model was introduced. Results from injection experiments were subsequently incorporated into an artificial neural network to establish a predictive framework for injectability. Last, simulations and experimental results contributed to the design of a syringe that maximizes injectability in vitro and in vivo. The custom injection system enabled a sixfold increase in injectability of large microparticles compared to a commercial syringe. This study highlights the importance of the proposed framework for optimal injection of microparticle-based drugs by parenteral routes.

A review on multi-physics numerical modelling in different applications of magnetorheological fluids

Magnetorheological fluids involve multi-physics phenomena which are manifested by interactions between structural mechanics, electromagnetism and rheological fluid flow. In comparison with analytical models, numerical models employed for magnetorheological fluid applications are thought to be more advantageous, as they can predict more phenomena, more parameters of design, and involve fewer model assumptions. On that basis, the state-of-the-art numerical methods that investigate the multi-physics behaviour of magnetorheological fluids in different applications are reviewed in this article. Theories, characteristics, limitations and considerations employed in numerical models are discussed. Modelling of magnetic field has been found to be rather an uncomplicated affair in comparison to modelling of fluid flow field which is rather complicated. This is because, the former involves essentially one phenomenon/mechanism, whereas the latter involves a plethora of phenomena/mechanisms such as laminar versus turbulent rheological flow, incompressible versus compressible flow, and single- versus two-phase flow. Moreover, some models are shown to be still incapable of predicting the rheological nonlinear behaviour of magnetorheological fluids although they can predict the dynamic characteristics of the system.

Numerical investigation of magnetic-field induced self-assembly of nonmagnetic particles in magnetic fluids

The underlying mechanisms of controlling the self-assembly of micro-size nonmagnetic particles (NPs) in magnetic fluids are essential for the manufacture, process and exploitation of nano-magnetic material. In this study, a multi-physical numerical model, which couples a distribution function correction-based immersed boundary lattice Boltzmann method (DFCIB-LBM) for fluid–structure interaction (FSI) and a self-correcting procedure of Poisson equation solver for magnetic field, is carried out to investigate such self-assembling behaviors and mechanisms. The interactions of two neighboring micro-size NPs placed in different distance and orientation, and the self-assembling behaviors of numerous micro-size NPs under uniform magnetic field are studied in details. The results demonstrate that the self-assembling behaviors are caused by the inverse magnetic effect, which can be adjusted by varying the concentration and size of NPs, permeability ratio, and the strength of external magnetic field. On the contrary, NPs in magnetic fluid affect their surrounding magnetic field and hinder the magnetization near the NP boundary region. These findings can provide a better understanding of the bottom-up fabrication of magnetic functional materials and devices.

A numerical study on the performance of a converging thermoelectric generator system used for waste heat recovery

Structure-based optimization is an effective approach to improve the performance of thermoelectric generators. Aiming to increase the heat transfer and hot side temperature of the heat exchanger, a converging heat exchanger design is developed in this study. Furthermore, a multiphysics fluid-thermoelectric coupled field numerical model is proposed, which is used to perform comprehensive numerical simulations to evaluate the behaviour of the thermoelectric generator system. The results indicate that the converging thermoelectric generator system generates a higher output power, induces a lower backpressure power loss, and has a more uniform temperature distribution than the conventional structure. The output power of the converging thermoelectric generator system is approximately 5.9% higher than that of the conventional system at an air temperature of 550 K and an air mass flow rate of 60 g/s. Moreover, the power increment provided by the converging design increases with increasing air temperature and decreasing air mass flow rate. The maximum deviation in the output power between the numerical and experimental results is 2.4%, which validates the performance of the multiphysics fluid-thermoelectric coupled field numerical model. This work provides new insights for numerical investigations of thermoelectric generator systems and presents a novel concept for optimizing the exhaust gas channel of a heat exchanger.

Behavior of ultrafine particles in electro-hydrodynamic flow induced by corona discharge

Ultrafine particle behavior in electro-hydrodynamic (EHD) flow induced by corona discharge is studied experimentally and numerically. The EHD flow serves as a primary particle aspiration/sampling mechanism, the collector does not require any additional flow generation. Multiphysics numerical model couples the ion transport equation and the Navier-Stokes equations (NSE) to solve for the spatiotemporal distribution of electric field, charge density, and flow field, the results are compared with experimental velocity profiles at the exit. The computed velocity and flow rate data are in good agreement with the experimental data; the maximum velocity is located at the axis and ranges from 1 m/s to 4 m/s as a function of corona voltage. Experimentally evaluated particle transmission trends for ambient and NaCl nanoparticles particles in the 20 nm–150 nm range are in good agreement with the theoretical models. However, for particles in the 10 nm–20 nm size range, the transmission is lower due to the increased particle charging resulted from their exposure to the high-intensity electric field and high charge density in the EHD driven flow. These conditions yield a high probability of particles below 20 nm to acquire and hold a unit charge. The transmission is lower for smaller particle (10 nm) due to their high charge to mass ratio, and it increases as the single-charged particles grow in mass up to 20 nm, resulting in their lower electrical mobility. For particles larger than 20 nm, the electrical mobility increases again as they can acquire multiple charges. The results shed insight into interaction of nanoparticle and ions in high electrical field environment, that occur in primary EHD driven flows and in the secondary flows generated by corona discharge.

Thermally induced diffusion of chemicals under steady-state heat transfer in saturated porous media

Thermally induced diffusion of chemicals is observed in many natural phenomena and engineering processes. We present analytical solutions to the non-isothermal diffusion of chemicals under combined effects of molecular and thermal diffusion processes and under variable diffusion coefficient with temperature. The generalized integral transform technique (GITT) is adopted to successfully derive the analytical solutions to the one-dimensional boundary problem under Neumann and Dirichlet outflow conditions. The accuracy of the analytical model developed is examined against three benchmarks including two experimental datasets. The analytical models are applied to develop an understanding of how the chemical transfer under non-isothermal conditions is governed by a combination of the Soret effect and temperature dependency of diffusion coefficient. We demonstrate that the mass transfer components due to thermal diffusion (or Soret effect) and the temperature dependency of diffusion coefficients are equally important to develop an accurate assessment of non-isothermal diffusion problem. Under the conditions of the case study considered, we show that a threshold for the Soret coefficient exists at which the temperature dependency of chemical diffusion coefficient can induce equally or larger influences on the chemical compared to the influence of thermal diffusion. The analytical solutions proposed also provide modelling benchmarks to examine the accuracy of alternative multiphysics numerical models for studying the non-isothermal diffusion problems in porous media.

On the Effects of Package on the PMUTs Performances-Multiphysics Model and Frequency Analyses.

This paper deals with a multiphysics numerical modelling via finite element method (FEM) of an air-coupled array piezoelectric micromachined ultrasonic transducers (PMUTs). The proposed numerical model is fully 3D with the following features: the presence of the fabrication induced residual stresses, which determine a geometrically non-linear initial deformed configuration of the diaphragms and a remarkable shift of the fundamental frequency; the multiple coupling between different physics, namely electro-mechanical-coupling for the piezo-electric model, acoustic-structure interaction at the acoustic-structure interface and pressure acoustics in the surrounding air. The model takes into account the complete set of PMUTs belonging to the silicon die in a 4 × 4 array configuration and the protective package, as well. The results have been validated by experimental data, in terms of initial static pre-deflected configuration of the diaphragms and frequency response function of the PMUT. The numerical procedure was applied, to analyze different package configurations of the device, to study the influence of the holes on the acoustic transmission in terms of SPL and propagation pattern and consequently extract a set of design guidelines.

Modelling of a thermoelectric generator for heavy-duty natural gas vehicles: Techno-economic approach and experimental investigation

Global CO2 emissions of heavy-duty vehicles are rising steadily and will continue to increase in the future without the implementation of measures such as technologies to reduce fuel consumption and emissions. In recent years, vehicles with natural gas-powered engines have increasingly been used as an economical and environmentally friendly alternative to diesel engines to reduce emissions. In addition to their lower emissions, these offer a high potential for waste heat recovery.A thermoelectric generator as a waste heat recovery system represents a cost-efficient technology for fuel and emission reduction. Integrated in the exhaust system, some of the otherwise lost heat can be converted to useful electrical energy. The advantages of thermoelectric generators compared to similar systems are low maintenance requirements and therefore a low cost-benefit ratio.This paper presents research on thermoelectric generator systems for heavy-duty natural gas vehicles on multiple levels. As a novelty, a holistic approach is applied, which includes interactions between all its components, all interactions with the overall vehicle system and the total cost of ownership. This approach is combined with a multiphysical numerical simulation model to obtain an economically suitable design. The solution of the simulation study is validated by an experimental investigation using a single channel system with commercially available thermoelectric modules. Approximately 70% of the simulated output power and the calculated efficiency could be measured.The proposed thermoelectric generator solution for heavy-duty natural gas vehicles achieves a peak power of 1507 W and a power density of up to 50 W kg−1. The results indicate a net fuel reduction of −0.54% (gross −1.04%). This is equivalent to a reduction of CO2 emissions of 4.9 (9.4) gCO2 km−1. The maximum system efficiency is simulative up to 4.2% (3.7% experimental). The overall system costs are estimated at 1811 EUR and thus represent a cost-benefit ratio of min. 1.2 EUR W−1. The results exceed the state of the art by more than 84%.The investigated commercially available thermoelectric modules with a power density of 1.1 W cm−2 are currently not application-oriented and are unable to fulfil the economic target of an amortization period of less than 3 years. New approaches are required and discussed. The new solution found with a power density of up to 3 W cm−2 and an efficiency of up to 9% indicates a high potential regarding the future cost-benefit ratio of the technology and will be adopted for further research and development activities.

Optimization and performance analysis of a solar concentrated photovoltaic-thermoelectric (CPV-TE) hybrid system

This work presents, for the first time, a statistical model to forecast the electrical efficiency of concentrated photovoltaic-thermoelectric system (CPV-TE). The main objective of this work is to analyze the impact of the input factors (product of solar radiation and optical concentration, external load resistance, leg height of TE and ambient temperature) most affecting the electrical efficiency of CPV-TE system. An innovative and integrated approach based on a multi-physics numerical model coupling radiative, conductive and convective heat transfers Seebeck and photoelectrical conversion physical phenomena inside the CPV-TE collector and a response surface methodology (RSM) model was developed. COMSOL 5.4 Multiphysics software is used to perform the three-dimensional numerical study based on finite element method. Furthermore, results from the numerical model is then analysed using the statistical tool, response surface methodology. The analysis of variance (ANOVA) is conducted to develop the quadratic regression model and examine the statistical significance of each input factor. The results reveal that the obtained determination coefficient (R2) for electrical efficiency is 0.9945. An excellent fitting is achieved between forecast values obtained from the statistical model and the numerical data provided by the three-dimensional numerical model. The influence of the parameters in order of importance on the electrical efficiency are respectively: product of solar radiation and optical concentration, the height legs of TE, external electrical resistance load, and ambient temperature. A simple polynomial statistical model is created in this work to predict and maximize the electrical efficiency from the solar CPV-TE system based on the four investigated input parameters. The maximum electrical efficiency of the proposed CPVTE (17.448%) is obtained for optimum operating parameters at 229.698 W/m2 value of product of solar radiation and optical concentration, 303.353 K value of ambient temperature, 2.681Ω value of resistance electrical load and at 3.083 mm value of height of TE module.

Simulation of macrosegregation in direct-chill casting—A model based on meshless diffuse approximate method

A multiphysics numerical model has been developed for prediction of macrosegregation in direct-chill casting. The model uses volume averaged mass, momentum, energy, and species conservation equations to simulate the solidification of axisymmetric aluminium-alloy billets. The boundary conditions for the heat transfer include the effects of hot top, mould chill, and direct chill. The volume averaged conservation equations are solved with the explicit local meshless diffuse-approximate method. The approximation coefficients are evaluated on subdomains containing 14 nodes with the second order polynomial basis and the Gaussian weight function. Problems with instabilities due to strong convection are successfully eliminated with an adaptive shift of the weight function and evaluation position in the upstream direction. The automatic adaptive generation of computational node arrangement decreases the calculation time and in a straightforward way enables investigation of the complex flow for geometrically different inflow structures, including sharp and curved edges. The model is used for casting simulation of an Al-5.25wt%Cu alloy billet with a 120 mm radius for various inlet designs. The effect of inlet geometry on the temperature, solid fraction, melt flow, and macrosegregation is investigated. The described developments represent a first meshless numerical approach for simulation of macrosegregation of an important industrial process.

Three-Dimensional Modeling of All-Solid-State Lithium-Ion Batteries Using Synchrotron Transmission X-ray Microscopy Tomography

In this study, a synchrotron transmission X-ray microscopy tomography system has been utilized to reconstruct the three-dimensional (3D) morphology of all-solid-state lithium-ion battery (ASSB) electrodes. The electrode was fabricated with a mixture of Li(Ni1/3Mn1/3Co1/3)O2, Li1.3Ti1.7Al0.3(PO4)3, and super-P. For the first time, a 3D numerical multi-physics model was developed to simulate the galvanostatic discharge performance of an ASSB, elucidating the spatial distribution of physical and electrochemical properties inside the electrode microstructure. The 3D model shows a wide range of electrochemical properties distribution in the solid electrolyte (SE) and the active material (AM) which might have a negative effect on ASSB performance. The results show that at high current rates, the void space hinders the ions’ movement and causes local inhomogeneity in the lithium-ion distribution. The simulation results for electrodes fabricated under two pressing pressures reveal that higher pressure decreases the void spaces, leading to a more uniform distribution of lithium ions in the SE due to more facile lithium ion transport. The approach in this study is a key step moving forward in the design of 3D ASSBs and sheds light on the physical and electrochemical property distribution in the SE, active material, and their interface.

Numerical Simulation of Melt-Pool Hydrodynamics in μ-EDM Process

The machining efficiency and productivity of the micro-electrical discharge machining (μ-EDM) process can be enhanced by the fundamental insights on the plasma-material interaction, which can be appraised via experimental and numerical analysis of discharge crater formation. The high-power density with low pulse-duration results in the transformation of the solid workpiece into liquid and even vaporisation phase to generate a crater. The crater dimension largely depends on the extent of vaporization induced recoil pressure as well as the pressure exerted by the expanding plasma channel. Efforts have been made by the researchers to analyse the plasma characteristics viz. its temperature, pressure and the role of plasma pressure on the material removal. However, there is a scarcity of the realistic data pertaining to precise plasma pressure which consequences in less accurate estimation of the numerically simulated crater. Moreover, the extent of evaporation is delayed due to activation of plasma pressure. Therefore, it is imperative to conduct a sensitivity analysis of variation of plasma pressure to improve the predictive nature of three-phase multi-physics numerical modelling of the μ-EDM.In the present paper, an endeavour has been made to consider the multi-phase transformation corresponding to the high-power density applied to the workpiece. Further, the effect of parameters such as Marangoni convection, Young Laplace surface tension pressure, vapour induced recoil pressure and a time-varying plasma pressure on the melt-pool hydrodynamics are considered. A 2D phase-field numerical model for the machining of Ti-6Al-4V has been formulated considering the aforementioned parameters. The numerical model is implemented in the commercial finite element method (FEM) software COMSOL Multiphysics. The simulation results reveal that the material removal in the initial phase of pulse-duration is dominated by vaporisation along with the melt expulsion due to recoil pressure which governs the crater size. The vaporisation of the Ti-6Al-4V is delayed to 4250 K due to active plasma pressure in the melt-pool. In the remaining pulse period, the surface tension induced backflow of molten metal along with Marangoni convection result in non-uniform perturbation at the bottom of the crater. Finally, the simulated crater is validated with the experimentally determined one-off crater using a dedicated single spark EDM circuit.