Thermal vibrational and gravitational analysis of a hybrid aqueous suspension comprising Ag–MgO hybrid nano-additives

The incorporation of simultaneous passive and active techniques for enhancing heat transfer has been a promising area of research in the last decades. As such, in the present study, thermal convection heat transfer of a hybrid nanofluid in a square cavity subjected to simultaneous effects of gravitational and vibrational forces has been addressed. Initially, the cavity, saturated with Ag-MgO hybrid nanofluid, is stagnant and in thermal equilibrium. Then, the sidewalls of the cavity are heated isothermally, and the cavity starts vibrating in a vertical direction. The upper and lower walls are kept adiabatic. Galerkin finite element method with a very small- and adaptive-time step has been used to precisely capture the impact of vibrational force on the flow and thermal fields in high frequencies. Impacts of vibration frequency, gravitational and vibration Rayleigh numbers, and the volume fraction of hybrid nano-additives are studied. It has been revealed that the external vibration amplifies the rate of heat transfer for all the studied frequencies. Moreover, although the presence of the nanoparticles seems to have a very limited effect on the effectiveness of heating, the effect of the nanoparticle concentration on the heat transfer intensity varies with time.