  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 $(0.6
\leq n \leq 1.0)$, the Darcy number $Da$ ranging from $(10^{-3} \leq Da \leq
10^{-1})$ and the Rayleigh number $Ra$ ranging from $(10^3 \leq Ra \leq 10^5)$.
Results show that the average Nusselt number ($\overline{Nu}$) decreases with
an increase in the value of $n$ while $\overline{Nu}$ 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.
