PurposeThis study aims to numerically explore natural convection and latent heat transfer in a square porous cavity filled with a H2O/nano-encapsulated phase change material (NEPCM) mixture. Particular attention is paid to the influence of cavity geometry, block inclination and wall undulations on heat transfer and melting behavior.Design/methodology/approachThis setup includes a central, inclined, heated elliptical block and features a corrugated cold wall. The dimensionless governing equations under the local thermal equilibrium (LTE) assumption are solved using the Galerkin-based finite element method. An exhaustive parametric analysis is conducted to evaluate the influence of main parameters, including Rayleigh number (103-106), Darcy number (10-5-10-1), Stefan number (Ste) (0.2-1), porosity (0.1-0.9), nanoparticle volume fraction (0%-5%), fusion temperature (0.05-0.95), block tilt angle (0 degrees - 180 degrees) and wall undulation shape (sinusoidal, triangular and rectangular). Selected validations were adopted to ascertain simulation accuracy and consistency.FindingsIt turned out that increasing specific settings is the keynote to improving or mitigating the average Nusselt number (Nuavg). The findings highlighted that higher Rayleigh and Darcy numbers, as well as porosity and nanoparticles' volume fraction, improve the Nuavg, while a greater Ste mitigates thermal performance due to slower melting. An optimal fusion temperature is identified where latent heat absorption is maximized. Tilt angles close to 90 degrees improve vortex formation and heat transfer efficiency. In terms of thermal performance, sinusoidal and triangular wall geometries outperform rectangular geometries, especially for low undulations. Furthermore, this numerical study seems germane to latent thermal energy storage systems.Research limitations/implicationsFuture research could further explore thermal systems involving phase change and porous structures under additional factors, either by adding nanomaterials, encapsulating phase change materials, other boundary conditions or redesigning heat transfer surfaces to further improve their thermal performance.Practical implicationsThe geometric configuration considered herein has practical applications in different engineering sectors, such as solar energy, waste heat recovery from building materials, advanced electronics, cooling technologies, fuel cells, mixing processes and even nuclear energy and many more.Originality/valueTo the best of the authors' knowledge, this work is the first to provide new insights into the coupled effects of porous structures, latent heat storage and cavity geometry on the natural convection of H2O-NEPCM mixture in a cavity characterized by the Darcy-Brinkman model and the LTE assumption. The study of such a mixture in such a little-explored configuration revealed strong thermal interactions between conduction, convection and phase change. The obtained findings deal useful guidelines for the design of advanced passive cooling and high-efficiency latent heat energy storage systems.

The steady-state natural convective heat transfer and flow dynamics over a heat-generating cylindrical battery enclosed in a water- nano-encapsulated phase change material (NEPCM)-saturated porous cavity are numerically addressed. The generating cell is covered with a thermally conductive material (copper). The cavity exhibits left and right vertical walls of constant cold temperature (), and insulated lower and upper walls. Adopting the local thermal equilibrium (LTE) approach among the fluid and the porous structure, the dimensionless Darcy-Brinkman (DB) equations are numerically handled via the Galerkin weighted residual (GWR) based finite element method (FEM) associated with the Newton-Raphson scheme. The impact of key parameters was thoroughly studied to grasp the flow and heat transfer. The results, illustrated by streamlines, isotherms, heat capacity curves (melting-solidification zones), and maximum cell core temperature, highlight the substantive effect of these control parameters. An increase in was shown to significantly improve convection, thereby reducing the cell core temperature. It turned out that an increase in from 10-5 to 10-1 decreases by up to 22.6%. Likewise, a rise in porosity () from 0.1 to 0.9 sweeps away an additional reduction of 10.5%. Increasing NEPCM's seeding improves both thermal conduction and latent heat absorption, while a lower improves melting dynamics and thermal response. As for the heat release parameter , its effect seems to be the dominant, with almost linear increases in core temperature as increases. Comparisons to previous research corroborated the current findings. All in all, this study sheds light on the mechanisms of heat transfer in lithium-ion batteries (LIBs) and/or other thermal energy storage (TES) systems using a water-NEPCM mixture and paves the way for further application-based research.

This study presents a numerical investigation of mixed convection in a top lid-driven cavity filled with a Al2O3-H2O nanofluid and featuring an elliptical hollow block coated with a conductive strip using the multi-relaxation-time lattice Boltzmann method. The in-house-developed code numerically handles the two-dimensional problem after being validated by comparison with available results. The issue is thoroughly inspected for various relevant parameters (Ri number, thickness Delta, thermal conductivities ratio of the strip K, and a seeding phi) such as 10-2 <= Ri <= 10+2, 2.5x10-2 <=Delta <= 10-1, 10-1 <= K <= 10+2, and 0%<=phi <= 5%. The Rayleigh and Prandtl numbers assigned are Ra=104 and Pr=6.2. The effects of these key parameters have been sharply highlighted via streamlines, isotherms, the mean Nusselt number, and the mean temperature. It is found that the average Nusselt number is higher in low Ri and Delta cases and high K. Interestingly, the isothermal block and the conductive strip can either promote or hinder the overall heat transfer of the system for the deemed range of Ri. For instance, decreasing Delta from 0.1 to 0.025 enhances heat transfer by approximately 18.62% at Ri=0.1 for K=1 and phi=0. Moreover, the effects of various parameters on the average Nusselt number are clearly demonstrated.

A 2D numerical model has been created to simulate the gas flow in a porous hydrogen (H2) and air-fed solid oxide fuel cell (SOFC) and analyze the generation of entropy involved via the major key contributing factors. On this basis, flow, thermal, and mass transfers have been numerically handled with a validated lattice Boltzmann method (LBM), including flow channels that have an impact on the entropy generation assessment. Flow, thermal, and mass paths have been simulated throughout the SOFC. It turned out that the ohmic losses are largely predominant compared with those of the other factors (irreversibilities due to fluid friction, heat transfer, mass/chemical transfer, and activation). In addition, under equal current density, the partially obstructed anode channel exhibits lower entropy generation compared with the free (unobstructed) anode channel, thereby indicating higher heat and mass transfer performance. These findings indicate the modeling efficiency considered and the potential of the LBM approach to address the processes involved in a porous H2 SOFC. SOFCs directly convert chemical energy into electrical energy, with high efficiency, strong reliability, and low emissions. SOFCs have become attractive for automotive and aerospace industries due to their energy flexibility. The design of their channels directly affects heat and mass transfer capability and their output performance. For a better view of the thermal performance of any thermal system, aspects such as pressure drop and entropy generation must be considered in addition to heat transfer factors. Entropy generation analysis is one of the most used techniques to refine the SOFC design and investigate their performance. This can be achieved by modifying the anode channel. One option is to partially obstruct the channel with differently shaped obstacles. Further, the numerical simulations can provide a solid reference point for future CFD models and are relevant to thermal dynamics in these devices and chemical-to-electrical energy conversion industries.

In this study, a numerical investigation of a magneto -hydrodynamic (MHD) and backward -facing nanofluidic flow was performed using the thermal lattice Boltzmann method (LBM) with multiple distribution functions to handle dynamic and thermal fields, including the magnetic force. The Cu-H 2 O based nanofluid is considered as the working fluid, and the Brinkman-Forchheimer model is adopted to mathematically formulate the porous medium. In addition, heat transfer, pumping power, thermal performance index, and entropy generation within a backward -facing step open-ended channel with adiabatic walls has been investigated. A preliminary comparison of the simulation outcome with available numerical results shows that the in-house built code aptly describes the nanofluid flow behavior and heat transfer process. Afterward, a parametric examination of the impact of Hartmann number (0.0 <= Ha <= 25), Darcy number (10 -3 <= Da <= 1.0), Eckert number (0 <= Ec <= 10), nanoparticles volume fraction (0% <= phi <= 4%), and magnetic field tilt (0 <= gamma <= pi/2) on streamlines, isotherms, friction factor (C f ), pressure drop, pumping power, average Nusselt number (Nu ), thermal performance index (PI), and average entropy generation ratio (S * ) has been conducted. Based av on the findings obtained, it can be stated that increases in the nanoparticles' volume fraction and Ha rise Nu av , pressure drop (Delta P), and pumping power (P pump ) occur. On the other hand, PI and S* drop when phi and Ha rise. Bejan's number has also been shown to increase with Ha. It also turned out that increasing the magnetic field tilt involves a rise in heat transfer, pressure drop, and pumping power, except for PI and entropy generation.

Unsteady laminar magnetohydrodynamic forced convection and entropy generation inside a backward-facing step (BFS) porous channel with Cu-H2O nanofluid under a tilted magnetic field is numerically handled using a thermal lattice Boltzmann method (TLBM) with two distribution functions. The Darcy-Brinkman-Forchheimer (DBF) equations filled up with the energy equation (with local thermal equilibrium assumption) have been drawn up as the governing equations model. Their numerical solutions unveiled streamlines, Nusselt number, pumping power, performance index and entropy generation, and impacts of influential parameters (Hartmann number (Ha = 0; 10; 20; 100, 200), Darcy number (Da = 10-3; 10-2; 10-1), magnetic tilt angle (gamma = 0, pi/4, pi/2), nanoparticles' volume fraction (phi = 1 - 4%), medium porosity (epsilon = 0.6, 0.7, 0.8). The irreversibility analysis is also addressed to highlight the flow behavior. Regarding the validation of the modeling approach deemed, a consensus has been achieved with results available in the literature. Computations revealed that the volume fraction provides a fair performance rating with moderate pumping power. Likewise, the average Nusselt number, the average entropy generation, the pumping power and the performance index have a direct relationship with the Hartmann number, the nanoparticles volume fraction and the magnetic field tilt. Moreover, it can be stated the Cu-H2O nanofluid that seems worthwhile in terms of heat transfer efficiency compared to other examined nanofluids. Entropy generation due to the magnetic field was identified as the main source of irreversibility processes in all cases. Based on the outcomes, it is thought that applying a magnetic field can help minimize entropy generation in practical applications.

This paper proposed to use the impinging jets mixing process to improve the quality of residential heating and air conditioning. The main objective is to meet the requirements of occupants in terms of thermal comfort and air quality by proposing an optimal solution for the thermal homogenization improvement in the rooms by changing of the diffusers geometry and their arrangement in the ventilation and air-conditioning devices in blowing systems. This study involves both experimental and numerical studies of a three diffusers configurations composed of four peripheral jet with similar geometries and a central jet with a different geometry. All the configurations consist of four equidistant peripheral swirling jets, only the central jet that makes the difference between them. The configuration 1 includes a swirling central jet, on the other hand a circular central jet for the configuration 2 and finally a lobed central jet for configuration 3. The velocity and temperature distributions of the three configurations are investigated experimentally and numerically. Experimentally, the multifunction thermo-anemometer have been used to measure flow temperature and velocity. The dynamic and temperature features are more radially spread and get better homogeneity in configuration 3 and this is due to the energy distribution on the radial plane, which is relatively better than configuration 1 and configuration 2. The second part deals with numerical predictions of the dynamics and thermal fields of the three configurations considered. The study was realized using a RANS-based turbulence model. The numerical results are in reasonable agreement with our experiments for the three configurations. With this study, detailed information on the structure of the resulting flow is very useful to deepen the understanding of the physics of jet interaction and to validate turbulence models. The turbulence simulation is realized by the k-ω-SST model. This model gives a satisfactorily predicts the axial drop in velocity and temperature over the entire study range, demonstrating its ability to handle the interaction between swirling and lobe jets. Our results show that the geometry of the central diffuser is essential. This allows the axial velocity to decrease faster than configurations 1 and 2. This increases lateral diffusion, resulting in better homogenization.

As buildings' energy consumption has become of outstanding importance, much more attention is being paid to passive solar design strategies such as Trombe walls (TWs) in view of their implementation. Nowadays, such a device is considered a promising alternative to ensure a transition to renewable energies. Thereby, a three-dimensional Computational Fluid Dynamics (3D CFD) numerical transient analysis of a passive Trombe wall integrated in a test room has been implemented to investigate dynamic and thermal fields prevailing there. Two configurations have been considered herein. The first configuration includes an uninsulated TW. In the second configuration, we propose an insulated TW. From the simulation results, the proposed idea would offer improved thermal performance where the conductive and convective flows are more pronounced and the temperature can be maintained within 16–21°C. Likewise, the outside temperature of the insulated TW can reach around 25°C.

This study aims to numerically reveal and assess the influence of inserts of different shapes partially obstructing the anode flow channel on flow characteristics, heat and mass transfer, and planar solid oxide fuel cell (SOFC) performance. To this end, a lattice‐based Boltzmann method is taken. Within this setting, trapezoidal, circular, and triangular shapes and inserts’ heights have been deemed. It turns out that trapezoidal and circular obstacles increase the fuel mass transport to the anode/electrolyte interface and effectively improve the SOFC's power density. As for triangular obstacles, their impact is negligible in terms of performance. Through the findings, it can be stated that it is the trapezoidal design that is better than the other designs. Further, the effect of the inserts’ height has also been assessed to set the optimal performance. It is found that the SOFC performance increases by 4% when using five trapezoidal obstacles with a 90% blocking rate compared to the unobstructed channel. However, in the case of the circular design with five blocks and a 90% blocking rate, the power density improves only about 2.3%. To sum up, improving SOFCs’ power density by designing the anode channel can be adopted to achieve optimal operations.

Latent energy storage, using phase change materials (PCMs), has the potential to improve energy system efficiency, help reduce the energy supply and demand gap, and to contribute significantly to energy savings. However, the dynamics of the phase-change process affects the system's efficiency. Coordination between the melting and solidification duration and the increase in energy demand is essential to exploit the full potential of PCMs. This study deals with an experimental investigation of the use of a static magnetic field (SMF) generated by magnets to control the melting and solidification of Octadecane as a PCM. It is then supported using heat transfer scaling laws. Experimental results demonstrate that a magnetic field of 240 mT can delay the phase change process by up to 23 % if applied opposite to the buoyancy force across the entire surface of the enclosure. The used scaling laws show that an extremely high magnetic field can suppress the convection effect, thus, extremely slowing down the phase change process since the PCMs have relatively low thermal conductivity. Also, it is found that PCMs with a low Prandtl number and high electrical conductance are more sensitive to the magnetic field effect and, thereby, are advocated for future studies. Finally, this work aims at the development of techniques that allow the control of the rate at which energy should be stored or released in a latent heat system with PCMs and coordinate it with the subjected temperature variations.

In this work, latent heat thermal energy storage system composed of porous metal foams with phase change material subject to pulsating fluid flow is investigated. The pulsating admission of such systems has not been thoroughly studied so far. Thus, the main motivation of the present study has been the investigation of the effect of pulsating admission in comparison with the constant through flow. The investigation is carried out numerically, utilizing the thermal lattice Boltzmann method, adopting a dual distribution function approach for calculating the dynamic and thermal fields, within the framework of an in-house developed code. The porous media is modeled at a macroscopic level by the representative elementary volume scale approach, utilizing the Brinkman–Forchheimer extended Darcy model, without assuming thermal equilibrium between the fluid phase and the solid foam. The phase change is modeled by an enthalpy–porosity approach. The main novelty of the work resides in the analysis of pulsating flow effects on melting and solidification of a phase change material embedded in porous metal foam, as this has not been investigated that thoroughly before. Furthermore, in difference to the previous work, detailed energy and exergy analyses incorporating entropy generation rates are presented, making up a further important novel aspect of the present work. A parametric study is performed covering a range of the porosity (0.7, 0.8, 0.9). For pulsating flow, variations in the amplitude (0.1, 0.5, 0.9) and Strouhal number (0.1, 1.0) are investigated. The analysis of the pulsating flow shows that small pulsation amplitudes speed up the melting rate and the heat spread. The overall system irreversibility is observed to decrease with decreasing Strouhal number. The dependence of the system irreversibility on the pulsation amplitude has been observed, however, to be different between charging and discharging phases, which has been an interesting result. During charging, it is observed that low amplitudes lead to low irreversibility. However, high amplitudes are observed to be correlated with low irreversibility during discharging. By comparison with the previous work, the superiority of pulsating flow compared to the constant flow in picking up the maximum energy storage while minimizing thermal losses is demonstrated.

Improving heat transfer using nanofluids has proven to be a promising option with many practical applications. However, the behavior of particles conveying energy for thermal transport depends closely on the dimensions of systems and channels where the flow evolves. Thereby, any fine thermal analysis should lean on a mesoscale approach applied at a microscale level. To this end, the multi-distribution functions–thermal lattice Boltzmann method has been taken to deal with convective heat flow and entropy generation in a channel with isothermal top–bottom walls and filled with a nanofluid (Cu/water). It was extended to simulate the flow governed by the Brinkman–Forchheimer Darcy model using the local thermal equilibrium assumption. The effects of nanoparticles’ volume fraction, Darcy number, porosity, heat capacity ratio and thermal conductivity ratio on heat transfer, entropy generation, average Nusselt number, and Bejan number are investigated. Among the salient results, it can be stated that the nanoparticles’ volume fraction increases heat transfer and entropy generation, but such a propensity can be affected by the porous medium permeability used. To sum up, the findings confirm the potential of the multi-distribution functions–lattice Boltzmann formalism to tackle forced nanofluid flows with heat transfer in porous media.

Dans ce travail, nous avons étudié numériquement l’influence des partitions sur le transfert de chaleur par convection naturelle et par rayonnement thermique dans une cavité inclinée d’un angle par rapport au plan horizontal. Les équations gouvernant le système sont résolues par la méthode des volumes finis. La cavité contient un nombre de partitions variant de 0 à 3. Nous avons conclu que: i) le rayonnement thermique augmente le transfert de chaleur au sein de la cavité, ii) plus le nombre de partition est grand, plus le transfert de chaleur est réduit.

Thermoforming involves warming thermoplastics using infrared sources to a desired state in an open oven at atmospheric pressure. The prediction of the distribution of the flux intercepted by the thermoplastic is generally modeled by assuming the surrounding medium transparent. It is within this framework that the present work is placed while aiming at the influence of the temperature and the humidity of the ambient air (gas) on the intercepted energy. To do this, the wide-band model is used to characterize the absorptivity of air vs. the temperature and absolute humidity at atmospheric pressure. The energy efficiency of the radiation emitted by a halogen source and intercepted by a flat surface has been characterized using the temperature of the source and the surrounding environment, humidity, and distance. The temperature of the considered source range 600 K-1500 K, while that of the humid air is in the range 400 K-1000 K for an absolute humidity range 10-80%. The absorptivity of the real gas is modeled by that of a gray gas and the surface-to-surface and volume-to-surface exchange areas are assessed via the Monte Carlo method. From this study, it appears that the error induced by the transparent medium assumption depends on the distance (between lamp and receiver), the lamp temper-ature, the gas temperature, and its humidity.

Sharing renewable energies, reducing energy consumption and optimizing energy management in an attempt to limit environmental problems (air pollution, global warming, acid rain, etc.) has today become a genuine concern of scientific engineering research. Furthermore, with the drastic growth of requirements in building and industrial worldwide sectors, the need for proper techniques that allow enhancement in the thermal performance of systems is increasingly being addressed. It is worth noting that using sensible and latent heat storage materials (SHSMs and phase change materials (PCMs)) for thermal energy storage mechanisms can meet requirements such as thermal comfort in buildings when selected correctly. However, as the operating temperature changes, a series of complex technical issues arise, such as heat transfer issues, leaks, corrosion, subcooling, supercooling, etc. This paper reviews the most recent research advances in the area of sensible and latent heat storage through the porous media as potential technology while providing useful information for researchers and engineers in the energy storage domain. To this end, the state and challenges of PCMs incorporation methods are drawn up, and an updated database of various research is provided while discussing the conclusions concerning the sensible and latent heat storage in porous media, their scopes of application and impact on energy consumption. In the light of this non-exhaustive review, it turns out that the adoption of porous matrices improves the thermal performance of systems, mitigates energy consumption and drops CO2 emissions while ensuring thermal comfort within buildings. In addition, at the representative elementary volume (REV) and pore scales, the lattice Boltzmann method (LBM) is examined as an alternative method to the commonly used, traditional numerical methods. These two approaches are compared based on results available in the literature. Through these means, their ability to handle latent and sensible heat storage process in a porous medium is demonstrated. To sum up, to be more complete, perspectives of sensible and latent energy storage technologies are covered.

The non-continuity of the drying process after sunset is one of the most significant limitations with solar dryers that has an impact on product quality and drying time. To overcome this problem, we installed a Thermal Energy Storage (TES) unit in an indirect solar dryer. Given the economic advantages offered by Sensible Heat Storage (SHS) systems and their availability, they are the best option to consider in a drying application. In this paper, we investigated a SHS unit integrated within a solar dryer under real meteorological conditions in eastern Morocco. The solar dryer with a storage system was simulated using the Computational Fluid Dynamics (CFD) approach, which was validated using experimental data from the literature. The research is mainly focused on the amount of material required, the proper porosity of the packed bed, and the overall performance of the solar dryer for various types of SHS materials. The obtained results proved that when compared to the case without storage, the efficiency of the solar dryer with sensible heat storage increased by about 2.47% at night. Regarding the study of different materials, granite stones showed better performance with a porosity of 40% and a packed bed thickness of 15 cm, where the temperature differences between the two cases with and without storage reached almost 5 at night.

This paper aims to highlight the effective means for improving jets auto-induction for their integration into the terminal units of cooling and heating air devices. However, their traditional design often does not consider the interaction of the jet. A study on the interaction between lobed multi-jet diffusers in unbalanced positions blown into an ambient fluid is performed herein to deal with this problem. The configuration consists of several turbulent jets blowing from diffusers with lobed geometry. It is made up of seven air jet diffusers with lobed geometries, including a central one and six other peripherals. The experimental and numerical investigation mainly dealt with the temperature and velocity profiles for three kinds of configurations. Configuration 1 is typified because the seven diffusers are all in the same plane. As for the second and third configurations, the central diffuser is axially offset or advanced by a diameter, respectively. Experimentally, the axial and radial temperature and velocity profiles results demonstrated the importance and role of the positional imbalance of the central jet relative to the peripheral jets in the mixing performance of the resulting lobed jet. Our findings showed that the relative position of the central jet is essential. It allows the axial velocity to be reduced speedily than in configurations 2 and 3. Lateral diffusion is thereby increased leading to better homogenization. In addition, the central jet for cases of the positional imbalance configurations drives the other adjacent jets. The second part is tuned on the numerical prediction of the dynamic and thermal fields of the three configurations considered. The study is validated using six RANS-based turbulence models. The different models provide reasonable agreement with the experiment on the three configurations. Through this investigation, detailed information on the structure of the resulting flow was very useful in deepening the understanding of the jet’s interaction physics and validating turbulence models. Among the turbulence models assessed, the k–ω SST model satisfactorily predicts the axial decrease in velocity and temperature over the whole of the studied domain, suggesting its ability to deal with the interaction between lobed jets.

A thorough understanding of the solid oxide fuel cell (SOFC) performance and reactants' distribution through modeling and numerical simulation has become essential. In this paper, a comprehensive numerical model based on a lattice-based Boltzmann method was developed to numerically handle gas flow in the partially blocked channel and concentration polarization in porous electrodes while assessing the performance of such a SOFC. After model validation with available experimental data, effects of the blocks height, their number, and the cathode/anode-side flow channel blockage are investigated. Block insertion has been shown to speed up gas progression while enhancing mass transport from the channel to the anode/electrolyte interface and that the performance of the involved SOFC is better compared to a straight channel. The findings demonstrate that the SOFC performance improves by increasing both the blocks number and their height. Specifically, a 90% block with five blocks would improve power density by 14.4%.

In this investigation, a comprehensive numerical analysis of the flow involved in an open-ended straight channel fully filled with a porous metal foam saturated and a phase change material (paraffin) has been performed using a single relaxation time lattice Boltzmann method (SRT-LBM) at the representative elementary volume (REV) scale. The enthalpy-based approach with three density functions has been employed to cope with the governing equations under the local thermal non-equilibrium (LTNE) condition. The in-house code has been validated through a comparison with a previous case in literature. The pore per inch density (10≤PPI≤60) and porosity (0.7≤ε≤0.9) effects of the metal structure were analyzed during melting/solidifying phenomena at two Reynolds numbers (Re = 200 and 400). The relevant findings are discussed for the LTNE intensity and the entropy generation rate (Ns). Through the simulations, the LTNE hypothesis turned out to be secure and valid. In addition, it is maximum for small PPI value (=10) whatever the parameters deemed. On the other hand, high porosity (=0.9) is advised to reduce the system’s irreversibility. However, at a moderate Re (=200), a small PPI (=10) would be appropriate to mitigate the system irreversibility during the charging case, while a large value (PPI = 60) might be advised for the discharging case. In this context, it can be stated that during the melting period, low porosity (=0.7) with low PPI (=10) improves thermal performance, reduces the system irreversibility and speeds up the melting rate, while for high porosity (=0.9), a moderate PPI (=30) should be used during the melting process to achieve an optimal system.

The streaming flow and convective heat transfer in a standing-wave thermoacoustic engine (SWTAE) filled with helium gas were numerically handled. The mathematical model depicting the flow and heat transfer occurring consists of the extended Brinkman–Forchheimer–Darcy equations under Boussinesq approximation and completed by the temperature equation based on local thermal equilibrium assumption. Their numerical resolution was performed using a thermal lattice Boltzmann method (TLBM) with the approximation of Bhatnagar–Gross–Krook (BGK) implemented in an in-house solver. Such an approach is further validated by a previous study available in the literature with good agreement. The phase variation of streaming velocity, the convective heat effect on Rayleigh streaming, and temperature gradient and porosity effects on SWTAE thermal efficiency have been investigated and amply commented on. It turned out that the convection effect on the acoustic velocity is mainly observed on the engine core hot side while it is negligible on the cold side. Likewise, its influence on the Rayleigh streaming is particularly detected at low thermal gradient and that the minimization of the Rayleigh effect improves the thermoacoustic conversion at large thermal gradient. On the other hand, such efficiency is improved with increasing the core porosity. Based on the findings obtained, the TLBM approach adopted seems suitable to predict such flow's behavior. Thereby, the present work opens up a new course to model and characterize the flow and transfer of heat by convection in a SWTAE.