Thermal and hydraulic performance of half-cone minichannel design for supercritical CO2 PCHE

The Printed Circuit Heat Exchanger (PCHE) is one of the promising application of heat exchangers in supercritical CO2 (scCO2) power cycles due to its high compactness and structural rigidity. In this study, an innovative minichannel design with half-cone fin is proposed to increase performance of PCHE and its thermal and hydraulic characteristics are investigated numerically. With the increase of diverging-converging ratio and rib height, and the decrease of pitch, heat transfer can be improved. The flow direction of fluid changes constantly due to the variable cross-section, resulting in large changes in velocity and pressure gradients and increased pressure drop. However, comparing with the traditional straight channel and zigzag channel, it can transfer more heat at the same pump power, especially at relatively low Reynolds number flows. In summary, the half-cone fin can not only benefit increasing the compactness of PCHE, but also has good reliability in advanced scCO2 power cycles.