Multicomponent Lattice Boltzmann Model Research Articles

Lattice Boltzmann Model Investigation of Simultaneous Imbibition/Evaporation in PEMFC Cathodic Catalyst Layer Using Reconstructed 3D Image Data from Transmission Electron Microscopy

Proton Exchange Membrane Fuel Cells (PEMFCs) are widely used and significant attention is directed towards optimizing of the cathode catalyst layer. The critical focus revolves around refining the multi-phase boundary of the electrically conducting carbon support, the ion-conducting ionomer, the catalyst particles as well as the pore space that can be either occupied by oxygen (feedstock) or water (product). Challenges related to mass transport limitations of oxygen towards these multiple-phase boundaries, also denoted as active sites, persist, especially when liquid water increasingly saturates the pore space (Fig. 1). Furthermore, the evaporated water additionally hinders oxygen transport in the gas phase1,2. This study focuses on the investigation of pore-scale transport mechanisms inside of the cathodic catalyst layer, taking into account the counter-current diffusion of oxygen and water vapor in the gas phase as well as the generation of liquid water that increasingly saturates the void space. For this purpose, a multi-phase and multi-component pore scale Lattice Boltzmann model (LBM), coupled to two-phase reaction, was implemented. The LBM is tailored based on previous works3,4, including the localized generation of water at constant current densities, the imbibition of the pore structure with water counter-currently to the diffusion of oxygen, and the simultaneous evaporation of water. An actual 3D cathode catalyst layer from a commercial membrane electrode assembly, reconstructed from transmission electron microscopy (TEM) image data, was employed. It was imaged using a source voltage of 200kV and a current of 2 nA. The scanned sample had an approximate total volume of 500 × 500 × 100 nm3. From this, a 3D domain of 138 × 138 × 58 nm3 was reconstructed for this study. A 2D cross-section of the reconstructed image is exemplarily shown in Fig. 1. The in-silico study of water and oxygen transport through the catalyst layer elaborates the relationship between the rates of water invasion and evaporation in dependence of current density and catalyst layer structure. The critical conditions for water flooding are evaluated for different process conditions. Fig. 1 Schematic representation of the cathode catalyst layer: The ionomer is represented in white; the carbon for electron connectivity is represented in gray; pore space for oxygen and water transport in yellow; the black circles represent the active sites, i.e., Pt-particles located at the multi-phase boundary of ionomer, carbon and oxygen-filled pores; the red circles represent the inactive sites, that have no connection to ion and/or oxygen transport pathways. References A. Suzuki et al., Int. J. Hydrogen Energy, 36, 2221–2229 (2011) https://www.sciencedirect.com/science/article/pii/S0360319910022913.M. El Hannach, M. Prat, and J. Pauchet, Int. J. Hydrogen Energy, 37, 18996–19006 (2012) https://www.sciencedirect.com/science/article/pii/S0360319912022069.S. Bhaskaran et al., Dry. Technol., 40, 735–747 (2022) https://doi.org/10.1080/07373937.2021.1898417.S. Bhaskaran et al., Int. J. Hydrogen Energy, 47, 31551–31565 (2022) https://www.sciencedirect.com/science/article/pii/S0360319922030932. Figure 1

A study on the distribution and movement of water in unsaturated cement paste by a multi-component multi-phase lattice Boltzmann simulation

The distribution of water inside concrete is a crucial factor that determines its mechanical performance and durability. In contrast to experimental investigation, numerical models provide a new way to visualize and characterize the actual situation of water in unsaturated cementitious materials. However, the interactions between different components are quite complex and they are rarely considered so far. In this work, a multi-component multi-phase (MCMP) lattice Boltzmann model is developed to distribute moisture in partially saturated cement paste, in which the interactions between water and air are fully taken into account. The transport of water flow in unsaturated cement paste is modelled and the permeability is thus computed. The simulation results show a satisfactory agreement with experimental data, validating the proposed approach. The obtained permeability is found to decline at a decreased water saturation degree and this is attributed to a reduced number of transport paths for water flow. Moreover, as the contact angle increases from 80° to 100°, large pores become the preferred place for water to accumulate and the formed clusters are observed. According to the results, a strong correlation between pore structure (i.e., pore size and pore connectivity) and water permeability is found and discussed.

Effect of the angle of wedge-shaped hydrophilic patterns on drop evaporation and contact line behaviour: A lattice Boltzmann study

Hypothesis:Angular hydrophilic patterns can manipulate the drop morphology for applications like inkjet-printing. It is hypothesized that such patterns can also affect the contact line behaviour and evaporation rate of drops in a dynamic way, further affecting the quality of depositions. Here, the effect of the angular region is quantified using a wedge-shaped pattern. Experiments:The pseudo-potential multicomponent lattice Boltzmann (LB) model is used for the diffusion-limited (isothermal) evaporation of pinned liquid drops from wedge-shaped hydrophilic patterns. Findings:The contact line unpins the earliest at the apex region of the smallest wedge angles due to a pronounced difference between the local and overall contact angles. The difference reduces linearly with increasing wedge angles, leading to their delayed unpinning. The evaporative flux along the contact line is initially independent of the contact angle but reduces sharply near the unpinning angle. The variation of flux across wedge angles depends more on unpinning timings, as maximum flux values did not differ significantly. The evaporation rate is dynamic, with the smaller wedge angles initially exhibiting a higher evaporation rate because of larger drop surface areas, while the larger wedge angles dominate later owing to the delayed unpinning and retaining larger drop surface areas.

Enhancing flow boiling using a microchannel with pillar–cavity mixed structures: A lattice Boltzmann study

Enhancement of flow boiling in microchannels through adjusting surface structures has attracted much attention in recent years. However, most of the existing studies focus on homogeneous surface structures. In the present study, a novel vertical microchannel with pillar–cavity mixed structures is conceived to enhance flow boiling heat transfer. In the mixed microchannel, cavities and pillars are distributed on the vertical sidewalls of the upstream and downstream flow channel, respectively. A multicomponent phase-change lattice Boltzmann model is employed to investigate the flow boiling performance of the mixed microchannel. Numerical results show that the cavities in the mixed microchannel can supply effective nucleation sites for timely departure of bubbles, while the pillars in the mixed microchannel can suppress the expansion of the vapor film from the outlet toward the inlet. Moreover, the bubbles from the upstream cavities can entrain the cold liquid to disrupt the vapor film covering the downstream pillars for the rewetting of the heated surface. As a result, the flow boiling performance can be significantly enhanced by the synergistic effect of the pillar and cavity structures, and the best flow boiling performance can be achieved by controlling the ratio of the number of cavities to the total number of structures in the mixed microchannel to optimize the synergistic effect. The influences of the structural parameters of pillars and cavities on the flow boiling performance have also been studied. It is found that the height of the pillars and the depth of the cavities have important influences on the flow boiling performance, while the boiling performance is not sensitive to the width of the pillars.

Thermodynamic effects of gas adiabatic index on cavitation bubble collapse

In this paper, an improved multicomponent lattice Boltzmann model is employed to investigate the impact of the gas properties, specifically the gas adiabatic index, on the thermodynamic effects of cavitation bubble collapse. The study focuses on analyzing the temperature evolution in the flow field and the resulting thermal effects on the surrounding wall. The accuracy of the developed model is verified through comparisons with analytical solutions of the Rayleigh-Plesset equation and the validation of the adiabatic law. Then, a thermodynamic model of cavitation bubble composed of two-mixed gases collapsing near a wall is established to explore the influence of the gas adiabatic index γ on the temperature behavior. Key findings include the observation that the γ affects the temperature of the first collapse significantly, while its influence on the second collapse is minimal. Additionally, the presence of low-temperature regions near the bubble surface during collapse impacts both bubble and wall temperatures. The study also demonstrates that the γ affects maximum and minimum wall temperatures. The results have implications for selecting specific non-condensable gas properties within cavitation bubbles for targeted cooling or heating purposes, including potential applications in electronic component cooling and environmental refrigeration.

Pore-Scale Investigation of Mass Transport in Compressed Cathode Gas Diffusion Layer of Proton Exchange Membrane Fuel Cells

Proton exchange membrane fuel cells (PEMFCs) are considered a promising energy source in the field of transport and distributed power generation. Fundamental research into their key components is needed to improve PEMFC performance and accelerate commercialization. Binder addition and compression induced by assembly pressure can significantly change the microstructure of the gas diffusion layer and affect mass transport. A two-dimensional multicomponent lattice Boltzmann (LB) model considering the cathode electrochemical reaction was developed, and a GDL was reconstructed numerically and considering a binder structure. The effects of the binder and compression on mass transport and electrochemical performance within the GDL were investigated. The results showed that an increase in binder volume fraction led to more chain-like structures and closed pores that were unfavorable for mass transport. Compression increased the mass transfer resistance of the GDL in the region under the rib, leading to a decrease in oxygen concentration and local current density.

A non-uniform magnetic field coupled lattice Boltzmann model and its application on the wetting dynamics of a ferrofluid droplet under gravity effects

To extend the mesoscopic model for simulating the wetting dynamics of ferrofluid droplets, an improved multicomponent multiphase pseudopotential lattice Boltzmann (LB) model coupled with the magnetic field solver is constructed in this work. Through a series of validation studies, the accuracy and reliability of the proposed coupled model are ensured. The ferrofluid droplet is subjected to the effects of non-uniform magnetic field and gravity. The influences of various magnetic Bond numbers (Bom) and gravitational Bond numbers (Bo) on the wetting dynamics of a ferrofluid droplet on a hydrophobic surface are discussed, and the mechanism behind the morphological evolution of the ferrofluid droplet is unveiled. The results show that the curvature of the phase interface is a key factor influencing both the magnetic field intensity distribution around the phase interface and the pressure distribution inside the ferrofluid droplet, thus changing the evolution of the droplet morphology. The variation of Bom has a monotonic impact on the morphological evolution of the ferrofluid droplet and its equilibrium state, while the effect of the Bo depends on the magnitude of Bom. At Bom=49.98 and Bo=4.1, the ferrofluid droplet splits from the central position and into three parts in the end. The amplitude and duration time of the oscillation of the ferrofluid droplet increase with Bom. This study can provide a model reference and some key theoretical understandings for the numerical study of the wetting dynamics of ferrofluid droplets.

Effects of Cassie-Wenzel wetting transition on two-phase flow in porous media

Wettability is one of the most important factors affecting multiphase flow in porous media. In this study, effects of the dynamic wetting process on two-phase flow displacement are investigated at the pore scale. A time-dependent Cassie-Wenzel wetting transition model is improved and incorporated into the pseudopotential multiphase multicomponent lattice Boltzmann model. With the Cassie-Wenzel wetting transition considered, two-phase flow displacement is simulated in Voronoi porous media with structural disorder and layered characteristics under different capillary number and wetting transition characteristic time. The simulation results show that the wetting transition promotes cooperative pore filling and weakens the effect of nonuniformity of capillary resistance. Under different capillary number, increased wetting transition rate improves the wettability of invading fluid, and thus the saturation of invading fluid is increased. The results also show that the layered structure with decreased pore size along the flow direction compacts the displacement pattern and weakens the viscous fingering, leading to higher displacement efficiency. While in this layered structure, effects of the wetting transition are suppressed due to lower interfacial length between the invading fluid and solid surface. The simulation results provide new insights of the influence of the dynamic wetting transition and on fluid displacement in porous media.

Pore-scale simulation of gas displacement after water flooding using three-phase lattice Boltzmann method

Water flooding is a commonly used technique to improve oil recovery, although the amount of oil left in reservoirs after the procedure is still significant. Gas displacement after water flooding is an effective way to recover residual oil, but the occurrence state and flow principles of multiphase fluid after gas injection are still ambiguous. Therefore, the gas displacement process after water flooding should be studied on the pore scale to provide a basis for formulating a reasonable gas injection program. Most of the current pore-scale studies focus on two-phase flow, while simulations that account for the influence of oil-gas miscibility and injected water are seldom reported. In this work, the multi-component multi-phase Shan-Chen lattice Boltzmann model is used to simulate the gas displacement after water flooding in a porous medium, and the effects of injected water, viscosity ratio, pore structure, and miscibility are analyzed. It is established that the injected water will cause gas flow path variations and lead to premature gas channeling. Under the impact of capillary pressure, the water retained in the porous medium during the water flooding stage further imbibes into the tiny pores during gas injection and displaces the remaining oil. When miscibility is considered, the oil-gas interface disappears, eliminating the influence of the capillary effect on the fluid flow and enabling the recovery of remaining oil at the corner. This study sheds light on the gas displacement mechanisms after water flooding from the pore-scale perspective and provides a potential avenue for improving oil recovery. Cited as: Wang, S., Chen, L., Feng, Q., Chen, L., Fang, C., Cui, R. Pore-scale simulation of gas displacement after water flooding using three-phase lattice Boltzmann method. Capillarity, 2023, 6(2): 19-30. https://doi.org/10.46690/capi.2023.02.01

PORE SCALE INVESTIGATION ON THE EFFECT OF TEMPERATURE ON THREE-PHASE REACTIVE FLOW IN POROUS MEDIA USING THE LATTICE BOLTZMANN METHOD

In this study, the process of carbonate rock acidification with three-phase immiscible fluid [water, oil, and supercritical carbon dioxide (scCO<sub>2</sub>)] reactive flow in nonisothermal condition at pore scale was simulated by the lattice Boltzmann method (LBM). The three immiscible fluids' flow, solute transport, and heat transfer were solved by the Shan-Chen multiphase multicomponent lattice Boltzmann model, mass transport lattice Boltzmann model, and multicomponent thermal lattice Boltzmann model, respectively. The solid phase was updated by the volume-of-pixel method. In addition, the effect of temperature on the multiphase multicomponent reactive flow was numerically investigated. The results show that the dissolution rate is determined by three-phase distribution. The increase of temperature can accelerate the dissolution rate and decrease the inhibition influence of the non-acid phase on dissolution. Furthermore, the influence of temperature decreases with the increase of inlet velocity and oil wettability.

Numerical simulation of methane hydrate dissociation characteristics in microporous media using lattice Boltzmann method: Effect of fluid flow

A multi-phase multi-component lattice Boltzmann model for modeling the gas hydrate dissociation process is proposed, which takes into account the dissociation kinetics, gas-water migration, and heat-mass transfer processes. This model is validated by simulating the xenon hydrate dissociation process. Subsequently, the dissociation mechanism of methane hydrate in microporous media, the gas-water migration, and the effect of fluid flow on the dissociation are investigated by using the present model. The simulation results indicate that methane hydrate dissociation facing the inlet is faster than that away from the direction of inlet flow. Meanwhile, fluid flow promotes methane hydrate dissociation. In addition, the rapid dissociation process within the pore space may lead to a large amount of water production accumulation. Another noteworthy phenomenon is the observation of bubbles formed by liquid curling flows. Liquid curling is one of the reasons for bubble formation near the gas-liquid interface.

Cathode Electrochemical Performance of PEMFCs with Compressed Gas Diffusion Layer: A Pore-Scale Investigation

Proton exchange membrane fuel cells (PEMFCs) are one of the most promising power sources in the fields of vehicle and ship power. Compression caused by assembly pressure, freeze-thaw cycles, and mechanical vibration can cause changes in the microstructure of the gas diffusion layer (GDL), thereby affecting the mass transfer and electrochemical reaction processes inside the PEMFC. In this paper, a three-dimensional single-phase multi-component lattice Boltzmann (LB) model is established to investigate the effects of binder volume fraction and compression on the cathode electrochemical performance. The stochastic reconstruction method is employed to generate 20 GDLs with different binder volume fractions and compression ratios. Afterward, the reactive gas flow within the 20 GDLs is simulated, and the distribution of oxygen mole fraction, water vapor mole fraction, and the current density are analyzed. The simulation results demonstrate that the mean current density decreases with the increase of the compression ratio, and the optimal binder volume fraction of 20% resulted in the highest current density. This paper enriches the research on the cathode electrochemical performance of PEMFCs at the pore scale and provides a guideline for optimizing the GDL design.

Lattice Boltzmann Modeling of a Sessile and a Body Force-Driven Sliding Droplet over a Grooved Surface

This work presents the numerical modeling of a droplet’s sessile and dynamic behavior on a grooved surface. A droplet is placed on horizontal and vertical sliding conditions to observe its behavior under wettable and non-wettable conditions. The numerical analysis uses the multicomponent multiphase Shan-Chen Lattice Boltzmann Model (SC-LBM). The Cassie–Baxter and Wenzel states are reproduced for the sessile condition, and the enhancement of the contact angle is appreciated under the action of the grooved-ridged horizontal surface. The sliding droplet is analyzed through the Bond number by varying the ratio between the body force and the surface tension number. For Cassie–Baxter and Wenzel wettability conditions, a critical Bond number was discovered above which the sliding droplet will continue to deform indefinitely. The numerical model proved its suitability to predict the gradual deformation of a droplet over a grooved vertical surface subject to a tangential body force until the droplet eventually reaches a sessile condition or a breakup.

Asymmetric Condensation Characteristics during Dropwise Condensation in the Presence of Non-condensable Gas: A Lattice Boltzmann Study.

In this work, the condensation characteristics of droplets considering the non-condensable gas with different interaction effects are numerically studied utilizing a multicomponent multiphase thermal lattice Boltzmann (LB) model, with a special focus on the asymmetric nature induced by the interaction effect. The results demonstrate that for isolated-like growth with negligible interactions, the condensation characteristics, that is, the concentration profile, the temperature distribution, and the flow pattern, are typically symmetric in nature. For the growth regime in a pattern, the droplet has to compete with its neighbors for catching vapor, which leads to an overlapping concentration profile (namely the interaction effect). The distribution of the condensation flux on the droplet surface is consequently modified, which contributes to the asymmetric flow pattern and temperature profile. The condensation characteristics for droplet growth in a pattern present an asymmetric nature. Significantly, the asymmetric condensation flux resulting from the interaction effect can induce droplet motion. The results further demonstrate that the interaction strongly depends on the droplet's spatial and size distribution, including two crucial parameters, namely the inter-distance and relative size of droplets. The asymmetric condensation characteristics are consequently dependent on the difference in the interaction intensities on both sides of the droplet. Finally, we demonstrate numerically and theoretically that the evolution of the droplet radius versus time can be suitably described by a power law; the corresponding exponent is kept at a constant of 0.50 for isolated-like growth and is strongly sensitive to the interaction effect for the growth in a pattern.

A pseudopotential lattice Boltzmann model for simulating mass transfer around a rising bubble under real buoyancy effect

A pseudopotential multicomponent lattice Boltzmann (LB) model that can account for the real buoyancy effect is proposed to simulate the mass transfer process around a rising bubble. The density profiles at the equilibrium state are determined based on the hydrostatic condition and the zero diffusion flux condition (the balance of chemical potential). Compared with the LB models using effective buoyancy force, the proposed model has three advantages: (1) avoiding the unrealistic distribution of gas components within the bubble due to the upward effective buoyancy force, (2) removing the undesirable diffusion process due to the application of effective buoyancy force, and (3) considering the effect of the pressure gradient on the change of bubble size. In addition, Henry's law, which can be automatically recovered from the multicomponent LB equation, is re-interpreted from the perspective of the balance of chemical potential. Simulation results showed that the diffusion flux non-uniformly distributes over the surface of a rising bubble. The diffusion zone primarily occurs at the top and the lateral side of a rising bubble, whereas the diffusion transport just below the rising bubble is much less significant than its counterpart above the rising bubble. Various bubble shapes and their corresponding diffusion zones have been obtained. Moreover, the correlation between the Sherwood number and the Peclet number derived from the simulation results is consistent with those from previous numerical results. Thus, the proposed LB model is capable of conducting a quantitative analysis of the mass transfer around a rising bubble.

Pore-Scale Modeling of Mass Transport in Partially Saturated Cathode Gas Diffusion Layers of Proton Exchange Membrane Fuel Cell

Proton exchange membrane fuel cells (PEMFCs) have the advantages of high specific power, good stability, and zero emissions, making them clean and efficient energy conversion devices. Water management is one of the technical challenges limiting the development of PEMFC, with liquid water blocking the pores and increasing the resistance to mass transport. In this paper, a two-dimensional (2D) multiphase lattice Boltzmann (LB) model is developed to obtain the liquid water morphology within the gas diffusion layer (GDL). A 2D multicomponent flow Lattice Boltzmann model considering electrochemical reactions is established to investigate the effects of water saturation, activation overpotential, and pressure difference between the inlet and outlet gas channels on mass transport. At high water saturation, the liquid water forms water films within the GDL preventing reactive gas transport and water vapor are blocked near the catalyst layer making it difficult to remove. The PEMFC can achieve higher current densities at high activation overpotentials, but oxygen starvation will be exacerbated. Increasing the pressure difference between the inlet and outlet gas passages effectively increases the oxygen concentration and reduces the water vapor concentration in the GDL. The present study improves the understanding of the effect of GDL microstructure on mass transport and performance of PEMFC from the mesoscopic scale.

A Quantitative Comparison of Physical Accuracy and Numerical Stability of Lattice Boltzmann Color Gradient and Pseudopotential Multicomponent Models for Microfluidic Applications

The performances of the Color-Gradient (CG) and of the Shan-Chen (SC) multicomponent Lattice Boltzmann models are quantitatively compared side-by-side on multiple physical flow problems where breakup, coalescence and contraction of fluid ligaments are important. The flow problems are relevant to microfluidic applications, jetting of microdroplets as seen in inkjet printing, as well as emulsion dynamics. A significantly wider range of parameters is shown to be accessible for CG in terms of density-ratio, viscosity-ratio and surface tension values. Numerical stability for a high density ratio $\mathcal{O}(1000)$ is required for simulating the drop formation process during inkjet printing which we show here to be achievable using the CG model but not using the SC model. In terms of physical accuracy, the CG model shows good agreement with analytical solutions for droplet oscillation and ligament contraction test-cases. The SC model is effective in accurately simulating ligament contraction, but less accurate in handling droplet oscillations. Rayleigh-Plateau instability simulations show that both the CG and SC models give physically realistic results when breakup occurs, although smaller satellite droplets quickly vanish in the SC model due to droplet mass evaporating into the ambient phase. Our results show that the CG model is a suitable choice for challenging simulations of droplet formation, due to a combination of both numerical stability and physical accuracy. We also present a novel approach to incorporate repulsion forces between interfaces for CG, with possible applications to the study of stabilized emulsions. Specifically, we show that the CG model can produce similar results to a known multirange potentials extension of the SC model for modelling a disjoining pressure, opening up its use for the study of dense stabilized emulsions.

Consistent lattice Boltzmann model for reactive mixtures

A new lattice Boltzmann model (LBM) for chemically reactive mixtures is presented. The approach capitalizes on the recently introduced thermodynamically consistent LBM for multicomponent mixtures of ideal gases. Similar to the non-reactive case, the present LBM features Stefan–Maxwell diffusion of chemical species and a fully on-lattice mean-field realization of the momentum and energy of the flow. Besides introducing the reaction mechanism into the kinetic equations for the species, the proposed LBM also features a new realization of the compressible flow by using a concept of extended equilibrium on a standard lattice in three dimensions. The full thermodynamic consistency of the original non-reactive multicomponent LBM enables us to extend the temperature dynamics to the reactive mixtures by merely including the enthalpy of formation in addition to the sensible energy considered previously. Furthermore, we describe in detail the boundary conditions to be used for reactive flows of practical interest. The model is validated against a direct numerical simulation of various burning regimes of a hydrogen/air mixture in a microchannel, in two and three dimensions. Excellent comparison in these demanding benchmarks indicates that the proposed LBM can be a valuable and universal model for complex reactive flows.

Effect of lubricant addition on bubble motion of refrigerant CO2 in the nucleate boiling process

In this study, the influence mechanism of lubricating oil on the heat transfer of CO2 flow boiling was investigated from a mesoscopic perspective. A multiphase and multicomponent lattice Boltzmann model was proposed to simulate the rising motion of CO2 bubbles in CO2 with a small amount of lubricating oil based on the pseudopotential model. There are few simulations of multicomponent with different chemical compositions in existing studies. Moreover, the original pseudopotential model exhibited increasing instabilities at higher viscosity ratios. The model proposed in this study realized the mesoscopic simulation of a CO2/lubricant system by using an explicit forcing model to achieve numerical calculation under a high viscosity ratio and solve the evolution of the number density of each component to obtain the evolution of the macro parameters. The effectiveness of the model was verified using a Laplace's law simulation. Based on this model, the rising motions of single bubbles, double bubbles, and bubble groups under different oil concentrations were simulated. The effects of the lubricant on the rising velocity, morphology, and interaction of bubbles during bubble motion were analyzed in detail. The numerical results indicated that the variations in bubble shape decreased and drag force increased with the addition of oil. At an oil concentration of 0.05, the drag coefficient was 1.14 times higher than that under the oil-free condition. In addition, the presence of oil weakened the flow field disturbance caused by bubble interactions and resulted in the suppression for nucleate boiling.

TLBfind: a Thermal Lattice Boltzmann code for concentrated emulsions with FINite-size Droplets

In this paper, we present TLBfind, a GPU code for simulating the hydrodynamics of droplets along with a dynamic temperature field. TLBfind hinges on a two-dimensional multi-component lattice Boltzmann (LB) model simulating a concentrated emulsion with finite-size droplets evolving in a thermal convective state, just above the transition from conduction to convection. The droplet concentration of the emulsion system is tunable and at the core of the code lies the possibility to measure a large number of physical observables characterising the flow and droplets. Furthermore, TLBfind includes a parallel implementation on GPU of the Delaunay triangulation useful for the detection of droplets' plastic rearrangements, and several types of boundary conditions, supporting simulations of channels with structured rough walls. Program summaryProgram Title: TLBfindCPC Library link to program files:https://doi.org/10.17632/hbk45696nf.1Developer's repository link:https://github.com/FrancescaPelusi/TLBfindLicensing provisions: MITProgramming language: CUDA-CNature of problem: Hydrodynamics of concentrated emulsions with finite-size droplets in a thermal convective state.Solution method: Single relaxation time Lattice Boltzmann method to solve Navier-Stokes equations for fluids, coupled with the temperature field dynamics. The output describes the dynamics of finite-size droplets of concentrated emulsions in presence of a temperature field. The temperature field obeys the advection-diffusion equation.Additional comments including restrictions and unusual features: Plastic rearrangements of droplets are detected via the parallel implementation of the Delaunay triangulation, and boundary conditions are tunable.