Heat transfer enhancement of mixed convection in a square cavity with inlet and outlet ports due to oscillation of incoming flow

A numerical study of unsteady laminar mixed convection flow in a square cavity with ventilation ports due to an oscillating velocity at the inlet port is performed. It is found that after certain time duration, a periodic variation in the fluid flow and temperature field in the cavity are created. It is observed that the heat transfer is enhanced for all the Strouhal numbers investigated in comparison to its steady state case. To realize the optimizing Strouhal number to reach the best performance of the system, the total Nusselt number and the coefficient of pressure drop in a cycle of the oscillation is evaluated with respect to the Strouhal number. It is found that for a region of the Strouhal number between 0.5 and 1, the performance of the system will be desirable with considering both the maximum heat transfer rate and minimum pressure drop in the cavity. (C) 2011 Elsevier Ltd. All rights reserved.