Simulation of the printed circuit heat exchanger for S-CO₂ by segmented methods

Due to the advantages of high compactness, good pressure resistance, high heat transfer efficiency and high temperature resistance, printed circuit heat exchanger (PCHE) is a promising heat exchanger in the IV generation nuclear power plant, especially for supercritical carbon dioxide Brayton cycle. In this paper, the heat transfer characteristics and pressure drop in a straight PCHE are simulated. Three different thermal design methods, namely the logarithmic mean temperature difference method (LMTD), the constant property segmented calculation method (CPSC) and the variable property segmented calculation method (VPSC) are adopted. The results show that the LMTD and CPSC are unsuitable for the PCHE calculation due to the significant variations of S-CO₂ thermal properties with temperature, including density, viscosity and specific heat while the VPSC can obtain more reliable results.