An experimental investigation has been performed on the convective heat transfer characteristics for a single phase laminar flow in microchannels. The test sample used in this experiment contains 20 rectangular microchannels which have hydraulic diameter of 700 μm. Distilled water was used as a working fluid. The experiments were conducted with the range of Reynolds number from 400 to 800, heat flux ranging from 35 to 85 kW/m~2 and the inlet fluid temperature of 20°C. As experimental results, it was found that thermal entry length is about 10 ～ 40 mm and convective heat transfer coefficient has values in the range of 4.6 ～ 6.4 kW/m~2°C except for thermal entrance region. A numerical analysis has been also carried out on the convective heat transfer and pressure drop in a microchannel. As the results of numerical analysis, correlations were suggested for the friction factor and Nusselt number as functions of Reynolds number in the fully developed region.
展开▼
