Lattice Boltzmann Simulation of Mixed Convection Around a Heated Elliptic Block Cylinder within a Lid-driven Square Cavity

Abstract

A numerical analysis of mixed convection flows and heat transfer in a square enclosure having a sliding wall containing an elliptical block heated by isothermal temperature has been carried out. The enclosure is full of air and cooling from its sides by a cold temperature, whereas the remaining walls of the enclosure are considered thermally insulated. The mixed convection impact is attained by the heating elliptic block and moving upper wall. The investigation of fluid’s hydrodynamic and thermal behavior was examined by using Lattice Boltzmann Method (LBM) at different locations and orientations of the interior elliptical block for Richardson number, Ri, varying from 0.01 to 100 while the Rayleigh number, Ra, is fixed at 104. The findings indicate that the temperature pattern and flow structure are very responsive to the position of the elliptical block and Richardson number. Also, it is found that the heat exchange is very important for the block placed vertically close to the left wall or horizontally close to the bottom wall. More precisely, for Ri = 0.01, by moving the vertical block from the center towards the vicinity of the left/ (the right) surface, the heat transfer rate increases from 5.44 to 11.06/(8.36) with an increase of 103.30%/(53.67%). On the other hand, it is noted that the horizontal elliptic block favors heat evacuation in comparison with the vertical one. This study’s real-world impact lies in the potential to improve our understanding and, consequently, design more efficient cooling systems for electronic devices.