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This paper investigates conjugate natural convection heat transfer inside a water–Al2O3 nanofluid filled prismatic cavity having thick bottom wall. The governing Navier-Stokes and energy equations are solved using Galerkin finite element method. The effects of three heating conditions (isothermally, linearly-varying and sinusoidally varied temperature of the bottom wall) and different Raleigh numbers (103 ≤ Ra ≤ 107) on thermal field, flow field and entropy generation within the cavity have been depicted through isotherm, streamline and isentropic plots. Average Nusselt number along the top of the thick bottom wall and total entropy generation inside the cavity are also examined in order to estimate the influence of the above mentioned conditions. It is found that sinusoidal heating condition provides higher heat transfer rate for Ra ≥ 2×105. [ABSTRACT FROM AUTHOR]

This paper demonstrates a numerical study of heat transfer in a square porous cavity filled with non-Newtonian power-law fluid. A Graphics Processing Unit (GPU) has been used to accelerate the numerical simulation, which uses the Multiple-Relaxation-Time (MRT) Lattice Boltzmann Method. A modified power-law model has been employed to characterize the flow of non-Newtonian fluids. The simulations have been conducted for the power-law index n ranging from (0.6 ≤ n ≤ 1.0), the Darcy number Da ranging from (10−3 ≤ Da ≤ 10−1) and the Raleigh number Ra ranging from (103 ≤ Ra ≤ 105). Results show that the average Nusselt number (Nu) decreases with an increase in the value of n while Nu increases with an increase in the value of Da. Moreover, an increment in the value of Ra leads to an increase in the average Nusselt number. [ABSTRACT FROM AUTHOR]