Natural convection of Al2O3-water nanofluid in an inclined cavity using Buongiorno's two-phase model

In the present study, natural convection of Al2O3-water nanofluid and nano-particles local distribution inside a tilted square enclosure has been investigated using non-homogenous two-phase Buongiorno's model. The left and right vertical walls of cavity are kept at constant temperatures Th and Tc, respectively, while the other walls are thermally insulated. Using the finite volume method and the SIMPLE algorithm, the governing equations have been discretized. Simulations have been carried out for different inclination angle (0°≤θ ≤ 60°), Rayleigh number (102≤Ra≤106) as well as particle average volume fraction (φ) ranging from 0.01 to 0.04. Results show that at low Rayleigh numbers regardless of particle volume fraction, with increasing the inclination angle the average Nusselt number (NuAve) and heat transfer enhancement percentage remains almost constant. On the other hand, for high Rayleigh numbers NuAve rises and then reduces with inclination angle whereas, heat transfer enhancement percent continuously increases with increasing inclination angle. It is also observed that for all inclination angles and at low Rayleigh numbers, the particle distribution is fairly non-uniform while, at high Ra numbers particles have nearly uniform distribution.