Numerical Study of Mixed Convection of Nano Fluid in a Lid-Driven Cavity Containing Hot Obstacles

A finite volume method is used to numerically study the mixed convection of aluminum oxide-water Nano fluid inside a square cavity containing hot quadrilaterals obstacles on its bottom wall. The effects of Rayleigh number, volume fraction of Nano particles and the height of hot obstacles are investigated. The results are shown through streamlines and isotherm curves as well as Nusselt number. The average size of Nano particles and the temperature of Nano fluid are 40 nm and 300 K respectively. The applied rang of Rayleigh number is between 104 and 105, for volume fraction of Nano particles between 0 and 0.06, and for height of obstacles between 0.1 and 0.2 of the height of cavity. The results show that the increase of Rayleigh number as well as volume fraction of Nano particles will increase the heat transfer inside the cavity. Furthermore, the increase of the height of obstacles reduces the average Nusselt number. A comparison with experiments was made to validate the results.