Appropriate sizes of porous and solid blocks for heat transfer under an impinging jet

A study of appropriate sizes of both porous and solid blocks mounted on a heated region impinged by a laminar slot jet was investigated numerically. A numerical method of SIMPLEC is adopted to solve governing equations, and a one-equation thermal model with Van Driest's wall function is considered for solving the energy equation of the porous block. The results indicated that enhancement of heat transfer is obtained for both shorter porous and solid block cases and decreasement of heat transfer occurs for longer block cases. Compared with the without block case, there exists an appropriate length of the porous block to gain the maximum thermal enhancement efficiency. As for the solid block case, as the length becomes shorter, the thermal enhancement efficiency becomes better.