ENHANCED FLOW BOILING OF OPEN MINI-CHANNEL AND JET IMPINGEMENT COOLING SCHEME BY SEPARATING LIQUID-VAPOR PATHWAYS

With the increase in the power density of light-emitting diodes, in order to prolong their lifetime, the development of cooling schemes with high heat dissipation performance has attracted much attention. Mini/micro-channels and jet impingement, as the typical technologies, have been widely studied in the past decades. However, there is no good solution to the coalescence of bubbles in the channel, which hinders the liquid supplement from developing dry spots that trigger the critical heat flux. In this study, this dilemma was alleviated by separating the liquid-vapor pathways under the interaction of mini-channels and jet impingement. A cooling scheme of departing bubbles that does not interfere with the liquid supplement was proposed to achieve a heat flux of 546 W/cm2, and the mechanism of enhancement was interpreted by comparison with the literature and visualization experiments. A test module was constructed and tested using deionized water as the working fluid. A prediction model of the critical heat flux was proposed based on the force balance of a bubble on the sidewall, and the maximum error was 11.3%with the same volumetric flow rate of the mini-channel and jet impingement. These findings may have an impact on the further development of efficient cooling technologies.