Thermal Performance Analysis in a Zigzag Channel Printed Circuit Heat Exchanger under Different Conditions

In this study, the effect of axial heat conduction on thermal performance in a zigzag channel printed circuit heat exchanger (PCHE) with supercritical liquefied natural gas as the working fluid is studied by a numerical method under different conditions. The influence factors include Reynolds number, operating pressure, inlet temperatures of the cold side, and wall thermal conductivity. The results indicate that the axial heat conduction can greatly affect the thermal performance of the PCHE at low Reynolds numbers but decrease it at high Reynolds numbers for different working conditions. At the same average Reynolds number, the thermal performance of the PCHE decreases as the pressure increases, and the inlet temperature of 195 K provides the best thermal performance while the inlet temperature of 220 K is the worst among the three different inlet temperatures of the cold side. Furthermore, the reduction of wall thermal conductivity can improve the thermal performance of the PCHE due to the influence of axial heat conduction in the separation wall.