Effect of Phase Shift on Mixed Convection in a Rectangular Vented Cavity filled with a Nanofluid and Submitted to Periodic Heating

The characteristic of flow and heat transfer of Al2O3-water nanofluids flowing through a horizontal ventilated cavity is investigated numerically. The bottom wall is subjected to a sinusoidal hot temperature profile, whereas the other boundaries are assumed to be thermally insulated. In fact, the flow comes forcedly into the system from the bottom of the left vertical wall and leaves it from the top of the right one by suction. The simulations focus on the effects of different key parameters, such as Reynolds number (200 <= Re <= 5000), nanoparticle's concentration (0 <= phi <= 0.05) and phase deviation of the sinusoidal heating (gamma equal 0 or pi), on the flow and thermal patterns and heat transfer performances. The obtained results show that the presence of nanoparticles increases the heat transfer and the mean temperature within the cavity. In addition, the phase shift of the heating temperature may lead to periodic solutions for weaker values of Re and contributes to an increase or a decrease of heat transfer depending on the value of phi and the convection regime.