S-CO2 and LBE coupled heat transfer characteristics analysis in new layout PCHE

Numerical simulations are employed to analyze and evaluate the flow heat transfer between supercritical carbon dioxide (S-CO2) and lead-bismuth eutectic (LBE) in the through-channel Printed Circuit Heat Exchanger (PCHE) with various channel arrangements. The flow heat transfer characteristics are examined based on the optimal arrangement, which consists of "one-on-two" semicircular and circular mixing channels. The results indicate that the coupled heat transfer between the two fluids in the PCHE is predominantly influenced by the S-CO2 side. The heat transfer intensity on the S-CO2 side determines the lower limit of the overall heat transfer. The optimal channel diameter ratio, for a fixed plate thickness, is determined to be 2.25 for achieving the best coupled heat transfer between S-CO2 and LBE. Furthermore, this arrangement can be extended to similar conditions where the heat transfer coefficient of the hot-side fluid differs by more than 10 times from that of the cold-side fluid. These results provide valuable insights for designing heat exchangers for printed circuit boards.