Mixed Convection’s Lattice Boltzmann Analysis in Cavity Featuring a Hollow Elliptical Block

Abstract

This study presents a numerical investigation of mixed convection in a top lid-driven cavity filled with a [Formula: see text] 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 [Formula: see text], thermal conductivities ratio of the strip K, and a seeding [Formula: see text]) such as [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text]. The Rayleigh and Prandtl numbers assigned are [Formula: see text] and [Formula: see text]. 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 [Formula: see text] 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 [Formula: see text] from 0.1 to 0.025 enhances heat transfer by approximately 18.62% at [Formula: see text] for [Formula: see text] and [Formula: see text]. Moreover, the effects of various parameters on the average Nusselt number are clearly demonstrated.