Experimental investigation on the heat transfer characteristics of novel rectangle radial microchannel heat exchangers in two-phase flow cooling system for data centers

As electronic component technology becomes increasingly miniaturized, how to keep them from overheating is challenging. Advanced microchannel two-phase flow cooling technology attracts more and more attentions due to its much better performance when compared with conventional forced air convection cooling technology. To fundamentally alleviate the Ledinegg instability of two-phase flow, three novel rectangle radial expansion multiple microchannel heat exchangers are proposed and manufactured, with two types of cold plates and covers. Experimental investigation on the flow boiling heat transfer performance of three heat exchangers was carried out. The rectangular radial design effectively suppresses the reverse two-phase flow, without dry-out phenomenon occurred. The heat exchanger, with cutting in its cold plate and without gap in its cover, was finally clarified having the best performance. Under the operation conditions of heating load of 400 W and flow rate of 8 L h⁻¹, the maximum measured wall temperature, the calculated averaged heat transfer coefficient, and the pressure drop are 104 °C, 0.009 kPa, and 65.444 kW m⁻² K, respectively. This type of heat exchanger has the best dynamic performance on pressure drop, and its cover could be further investigated by enhancing the bubble departure. Contributions of this work are expected to directly optimize the pumped two-phase flow cooling system for data centers.