Experimental study on the forced convective flow in a channel with heated blocks in tandem

This study experimentally examines the forced convective How over two sequentially heated blocks mounted on one principal wall of a channel. The experiments, involving mass transfer, were carried out via the naphthalene sublimation technique (NST). By virtue of the analogy between heat and mass transfer, the results can then be converted to determine the heat transfer. In the experiments, the block spacings were set at 2, 4, 6. 8, 12, 16, and 22 and the Reynolds numbers were set at 1300 and 10(4) which correspond to the laminar and the turbulent convective How cases, respectively. Results show that the Sherwood number increases or decreases monotonically along the block surfaces in the laminar convection cases: while the hump and sharp increase in the Sherwood number can be found in the turbulent convection cases. This is attributed to the reattachment of the separating bubble and the flow impingement, respectively. Comparison between the experimental and numerical results is made and the effect of the block spacing on heal transfer is discussed. (C) 1998 Elsevier Science Inc. All rights reserved.