EFFECT OF NANOFLUID VARIABLE PROPERTIES ON MIXED CONVECTION FLOW AND HEAT TRANSFER IN AN INCLINED TWO-SIDED LID-DRIVEN CAVITY WITH SINUSOIDAL HEATING ON SIDEWALLS

Abstract

In this study, mixed convection fl uid fl ow and heat transfer in an inclined two-sided lid-driven cavity subjected to Al2O3–water nanofl uid (with diff erent particle diameters from 15 to 99 nm) has been investigated numerically. The geometry is a double lid-driven square cavity with sinusoidal temperature distribution on the left sidewall, while the right wall is kept at Tc. The top and bott om walls of the cavity, which move in opposite directions, are assumed to be insulated. The eff ects of inclination angle, Richardson number, nanoparticle volume fraction, temperature, and nanoparticle diameter based on recent variable property formulations are studied. The eff ects of an increase in Richardson number while the solid volume fraction is constant and eff ects of an increase in solid volume fraction when the Richardson number is kept constant are investigated. Also, the obtained results show that an increase in nanoparticle diameter infl uences the fl ow patt ern and isotherm contours inside the cavity relatively when the Richardson number is kept constant and the diameter is varied from 15 to 99 nm. As the mean nanoparticle diameter increases, the corresponding fl ow velocity decreases, and hence the heat transfer enhancement is reduced. The results indicate that as Richardson number increases, the average Nusselt number rapidly increases for diff erent values of dp. Moreover, the results have clearly indicated that the addition of Al2O3 nanoparticles has produced a remarkable enhancement on heat transfer with respect to that of the pure fl uid.