Numerical simulation of heat transfer in rectangular microchannel

Numerical simulation has been conducted for the investigation of heat transfer in a rectangular, high\u96aspect ratio microchannel with heat sinks, similar to an experimental study. Water at ambient temperature is used as working fluid and the heating power of 180 W is introduced via electronic cartridges in the solids. Three channel heights of 0.3 mm, 0.6 mm and 1 mm are considered and the Reynolds number is in the range of 300 to 2360, based on the hydraulic diameter. The study is mainly focused on the Reynolds number and channel height effects on microchannel thermal performance. Validation study shows that Nusselt number variations agree with the theory and other predictions very well, but the numerical predicted Poiseuille number has shown some deficits compared to the theory, same as observed by other researchers. It is found that the scaling effect only appears at small channel height of 0.3 mm, for both the friction factors and the thermal resistance. While the predicted friction factor agrees reasonably well with an experimental-based correlation, the theoretical significantly under-predicts it. The thermal resistance tends to become smaller at small channel height, indicating that the heat transfer performance can be enhanced at small channel height