Numerical Study of Mixed Convection Heat Transfer in a Cavity Filled with NonNewtonian Nanofluids Utilizing Two-phase Mixture Model

: In the present research, the problem of mixed convection flow of a non-Newtonian nanofluid in a lid-driven cavity is simulated using a two-phase mixture model. Nanofluid of water-copper in this problem shows a shear-thinning behavior. To study the effects of non-Newtonian fluid with power-law model on the amount of heat transfer, various power-law indices are considered. After applying the governing equations and related models in the computational code, its validation is done by simulating the problem with Newtonian and non-Newtonian fluid behavior and comparing the results with those of other researchers. Afterwards, simulation of the problem is accomplished for the Richardson numbers of 0.001-1 and power-law indices of 0.2-1 while the volume fraction of nanoparticles alters from 0 to 0.09. The obtained results show that the increase in Richardson number decreases the amount of heat transfer. For all Richardson number decrease in the power law index leads to a decrease in the average Nusselt number. Variation of volume fraction from 0 to 0.09 at the power law index of 0.2 leads to an approximate increase of 15.75% and 17.32% in the average Nusselt number for Ri=0.001 and 1, respectively.