s-CO2 Brayton 사이클에서 PCHE Wet cooling에 관한 연구

The s-CO2 (supercritical CO2) power cycles draws great attention as a next power generation cycle due to its high efficiency. Commonly, the s-CO2 power cycle adopts three PCHE (printed circuit heat exchanger) which shows great compactness and high pressure durability. Among the three heat exchangers, the PCHE cooler undergoes the urgent thermophysical property changes near pseudo critical temperature. Thus, it is hard to design the heat exchanger and to predict the heat exchanger performance. In this study, the discretized numerical analysis was performed and the comparison was conducted with experimental results. Several convective heat transfer coefficients were introduced and adopted to perform numerical analysis. Most correlation well predicted the heat transfer rate when heat exchanger outlet temperature is higher than pseudo critical temperature. However, there occurs relatively large error when CO2 exit temperature closes to pseudo critical temperature. Among the correlation, Dang and Hihara correlation showed the best accuracy and heat transfer rate prediction RMSE showed about 6.5%