Forced Convection in a Square Cavity With Inlet and Outlet Ports

A finite-volume-based computational study of steady laminar forced convection inside a square cavity with inlet and outlet ports is presented. Given a fixed position of the inlet port, the location of outlet port is varied along the four walls of the cavity. The widths of the ports are equal to 5, 15 and 25 percent of the side. By positioning the outlet ports at 9 locations on the walls for Re = 10, 40, 100 and 500 and Pr = 5, a total of 101 cases were studied. For high Re and with the shortest distance between the inlet and outlet ports along the top wall, a primary CW rotating vortex that covers about 70 to 80 percent of the cavity is observed. Similar cases with smaller Re exhibit identical flow patterns but with weaker vortices as Re is lowered. As the outlet ports is lowered along the right wall, the CW primary vortex diminishes its strength; however a CCW vortex that is present next to the top right corner covers a greater portion of the cavity. With the outlet port moving left along the bottom wall, the CW primary vortex is weakened further and the CCW vortex occupies nearly the right half of the cavity. The temperature fields are directly related to the presence of the multiple vortices in the cavity. Regions of high temperature gradient are consistently observed at the interface of the throughflow and next to the solid walls on both sides of the outlet port. Local Nusselt numbers are low at 3 corners when no outlet port is present in their vicinity, whereas intense heat transfer rate is observed on the two sides of the outlet port. Between these minima and maxima, the local Nusselt number can vary drastically depending on the flow and temperature fields. By placing the outlet port with one end at the 3 corners, maximum total Nusselt number of the cavity can be achieved. Minimum total heat transfer of the cavity is achieved with the outlet port located at the middle of the walls.