Flow and Heat Transfer Characteristic Study of Supercritical CO₂ in Printed Circuit Heat Exchanger

Printed circuit heat exchanger (PCHE) is a micro-channel heat exchanger with the benefit of high efficiency, and can endure high temperature and pressure. Based on these benefits, PCHE are widely used in marine engineering, nuclear engineering and solar thermal system. The flow and heat transfer characteristic of supercritical CO₂ (SCO₂) near pseudo-critical point in PCHE was numerically studied in this paper. The results show that the temperature distribution is the flattest when the SCO₂ fluid temperature reaches pseudo-critical temperature, because the effective thermal conductivity of the fluid is the largest. The convection thermal resistance of SCO₂ is the largest of the total resistance, and then is the conductive resistance, the smallest is the convection thermal resistance of water. The conductive resistance calculated by equivalent thickness method is larger than simulation.With the increase of Reynolds number, the enhancement of heat transfer near pseudo-critical point is enhanced.