Numerical Simulation of Flow, Natural Convection and Distribution of Nano Particles inside Trapezoidal Cavity using Buongiorno’s Model

Abstract

In the present study, natural convection of Al2O3–water nanofluid and nano-particles local distribution inside the trapezium enclosure has been investigated using non-homogenous two- phase Buongiorno’s model. The governing equations of the problem are momentum, energy and volume fraction of nanoparticles that are solved using the finite volume method and the SIMPLE algorithm. Diffusion and convective terms are discretized using a second-order central difference and upwind schemes. The left and right walls of cavity are kept at constant temperatures, while the other walls are thermally insulated. Simulations have been carried out for different inclination angles, including 0°, 30°, and 45°, Rayleigh number (102≤Ra≤104) as well as particle average volume fraction ranging from 0.01 to 0.04. Results show that at low Rayleigh number for a specific particle volume fraction, with increasing the inclination angle from zero to 45 degree, the average Nusselt number and heat transfer decreases 81%. On the other hand, optimum results were obtained for the inclination angle of 30 degree. The Nusselt enhancement percent was obtained 5.5 compared to the square enclosure and 6.8 compared to the inclination angle of 45 degrees. Results also showed a uniform distribution for nanoparticles in high Rayleigh numbers and in enclosures with different inclination angles.