Thermal analysis of the flow over porous blocks in the cavity is examined and the effects of the aspect ratio and porosity of the blocks on the flow field and heat transfer rates are predicted numerically. In the simulations, two blocks with three porosities and two aspect ratios are considered. Air is used as the working fluid. The equilibrium-based equations are accommodated in the analysis and the control volume approach is introduced to discretize the governing equations of flow and heat transfer. It is found that the aspect ratio and the porosity of the blocks influence the flow structure in the cavity. The Nusselt number of each block in the cavity improves significantly with increasing porosity: however. the influence of the aspect ratio on the Nusselt number is not significant, particularly for the Block 1. (C) 2007 Elsevier B.V. All rights reserved.