Investigations on Single-Phase Liquid Flow through Semi-Circular Microchannels

摘要

An experimental investigation has been conducted to explore the validity of classical correlations based on conventional size channels for predicting the flow and heat transfer behaviour in single-phase liquid flow through semi-circular microchannels. The test piece used in the experiment was made of copper and consists of ten microchannels in parallel having hydraulic diameter of 214 μm and 60 mm length of semi-circular shape. The experiments were performed with deionised water as coolant and Reynolds number ranging from 238 to 1250. The experimental results obtained for friction factors showed that conventional theory for fully developed laminar flow is applicable with the range of our experiments. Classical correlations for macrochannels are evaluated with average Nusselt number obtained for microchannel with the assumption of constant wall heat flux. Slight deviations were observed in the experimental results obtained for Nusselt number when compared with earlier correlations, due to conjugate effect, variation in measurement of interface temperature and neglecting heat transfer through other surfaces of MCHS. 3-D conjugate heat transfer analysis is performed numerically for steady state condition. To predict heat transfer rates accurately, the entrance effects, conjugate effects, axial heat conduction and boundary conditions must have to be carefully considered.