Numerical Study of Free Convection inside the Differentially Heated Cavity incorporating Variable Property Al2O3-H2O Nanofluid
The free convection in a partially heated square cavity with alumina-water nanofluid is investigated in this paper. The investigation is carried out at the three-volume fraction of nanoparticles (0, 0.03, 0.05), two Prandtl numbers (2.66, 6), and constant Grashof number (105) with three shapes of insulating obstacles (Square, Circular, and Rectangular). The results show that the nanofluid volume fraction and Prandtl number play a significant role in enhancing heat transfer. The user-defined function (UDF) is developed and computed to investigate the effect of nanoparticle diameter and its temperature-dependent viscosity on convection. The average Nusselt number (Nu) is higher with the change in temperature dependent viscosity, and increasing percentage concentration of the nanoparticles. The nanoparticle diameter increases the average Nu with the higher volume fraction of nanoparticles inside the nanofluid for all the obstacle geometries.