Thermal Lattice Boltzmann Simulation of Entropy Generation within a Square Enclosure for Sensible and Latent Heat Transfers

Abstract

This paper deals with the numerical simulation of heat transfer and entropy generation in a 2D square enclosure for convective melting. A thermal lattice Boltzmann method (TLBM) is used to handle the study, which has been conducted for Prandtl numbers from 0.02 to 70 at Rayleigh numbers of 10 4 and 10 5. The results are presented in terms of the total entropy generation, average Bejan number and average Nusselt number. Within the range considered for the key parameters, the entropy generation is found to be controlled by the heat transfer loss for low Prandtl numbers. However, for the large Prandtl numbers, its variation is dominated by shearing losses. Moreover, the presence of the latent heat state decreases the overall thermodynamic losses while increasing the quantity of heat transferred.

Experimental and numerical characterization of an impure phase change material using a thermal lattice Boltzmann method

“…It is worth recalling that the description and validation of the model adopted herein can be found in [21,45,46]. The numerical model will calculate the temperature and velocity fields for both from the enthalpy while taking into consideration the impurities' presence.…”

“…Thereby, the main aim targeted here is to provide an improved model that accounts for supercooling, convection and the modified enthalpy-temperature curve. To carry out this work, we consider the thermal lattice Boltzmann method (TLBM) [15][16][17][18][19][20] based on a partial bounce-back (PBB) approach [21][22][23] supplemented with an enthalpy-based model. This enhanced model provides a more accurate simulation of phase-change materials, can better predict the solidification and melting processes, and thus match the experimental results.…”

“…On the other hand, the multi-scale mesoscopic lattice Boltzmann method (LBM) has emerged to offer huge potential for solving complex thermo-fluidic problems involving morphological development of complicated phase boundaries [21][22][23][29][30][31][32][33] and recovers the Navier-Stokes and energy equations. In addition, it has been witnessed that the LBM stands out in major fields of classical fluid dynamics: multiple-scale flows and heat transfers with or without phase change process.…”

Entropy Generation Analysis of a Natural Convection Inside a Sinusoidal Enclosure With Different Shapes of Cylinders

“…The results were formed as streamlines, isotherms, velocity profiles with an average Nusselt number. The researches Basak et al (2011) Morsli and Sabeur-Bendehina (2014), Nejad (2017), Shi et al (2017), Yehya and Naji (2015) and Erbay et al (2003), studied entropy generation in square enclosures with different cases. Basak et al (2011) presented a square cavity subjected to linearly cool from the sides and hot isothermal bottom while the top assumed fully insulated to reach a minimum entropy generation.…”

“…The simulation results of coupled equations for the flow, energy and entropy generation were presented in terms of streamlines, isotherms, local entropy generation contours, and total entropy generation. Yehya and Naji (2015) employed the thermal lattice Boltzmann method to study convective melting for the square enclosure. The results were controlled in low Prandtl numbers by the heat transfer while its variation dominated by shearing losses for high Prandtl numbers.…”