Numerical Assessment of Conjugate Heat Transfer inside Inclined Cavity filled with Al2O3/Water Nanofluids using Lattice Boltzmann Method

This article deals with the study of the influence of nanoparticles on heat transfer and fluid flow characteristics within a two dimensional (2D) inclined cavity filled with Al2O3/water nanofluids. The cavity, subjected to sinusoidal temperature profile, was divided by a wall possessing finite thickness, featuring three conductive fins on its hot side. Numerical simulations were conducted using the lattice Boltzmann method (LBM), with validation against proven benchmark problems in the literature. The effects of the inclination angle (0°<δ < 90°), nanoparticle volume fraction (0<∅<0.05), Rayleigh number (10 ⁴ <Ra < 10 ⁶ ), and thermal conductivity ratio (1 < λ _k  < 100) on heat transfer and flow structure were analyzed through streamline and isotherm contour plots, as well as by evaluating the Nusselt number (Nu) at the cold wall. The findings demonstrated that the average Nu raised in relation to Ra, ∅, and λ _k . Optimal heat transfer rate was observed at an inclination angle of δ = 30°. Incorporating a 5% nanoparticle volume fraction into the pure fluid resulted in a 12.81% boost in the heat transfer rate. Additionally, enhancing the thermal conductivity of the partition and fins contributed to a notable improvement in thermal performance, with gains of up to 34.18. A proposed correlation was done to express the relationship between the Nu number and Ra, δ, and λ _k . This correlation holds significant implications for optimizing and designing heat transfer systems across a range of industrial applications.