Direct liquid cooling heat transfer in microchannel: Experimental results and correlations assessment

In this paper, the hydrothermal characteristics of direct liquid cooling in microchannel were experimentally investigated. The effects of heat flux, inlet temperature, volume flow rate and hydraulic diameter on the wall temperature non-uniformity, the heat transfer coefficient and the pressure drop were investigated. To assess the flow and heat transfer performance of direct liquid cooling in the microchannel, the coefficient of performance was proposed and compared with indirect liquid cooling. The experimental results reveal that the coefficient of performance of direct liquid cooling is 5 times higher than that of indirect liquid cooling. Furthermore, the applicability of the existing empirical correlations was evaluated for microchannel direct liquid cooling. New correlations were developed for predicting Nusselt number and Darcy friction factor, which generated the mean absolute relative error of 11.6% and 22.2%, respectively. The present work could provide valuable guidance for the design of microchannel condenser for engineering application.