Developing convective heat transfer in deep rectangular microchannels

Experimental results have been obtained for single-phase forced convection in deep rectangular microchannels. Two configurations were tested, a single channel system and a multiple channel system. The two systems are identical except for the lack of extended surfaces in the single channel system. In the case of the multiple channel system the channels are 251 mu m wide and the channel walls are 119 mu m thick. In both systems the channels are approximately 1000 mu m deep and define a projected area of 2.5 cm x 2.5 cm. All tests were performed with deionized water as the working fluid, where the Reynolds number ranged from 173 to 12 900. The experimentally obtained local Nusselt number agrees reasonably well with classical developing channel flow theory. Furthermore, the results show that, in terms of flow and heat transfer characteristics, our microchannel system designed for developing laminar flow outperforms the comparable single channel system designed for turbulent flow. (C) 1999 Elsevier Science Inc. All rights reserved.