Abstract

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.

摘要

本研究采用数值方法研究了不同工况下以超临界液化天然气为工作流体的曲折通道印刷电路板换热器（PCHE）轴向热传导对热性能的影响。影响因素包括雷诺数、工作压力、冷侧入口温度和壁热导率。结果表明，轴向热传导可以极大地影响PCHE在低雷诺数下的热性能，但在不同工作条件下在高雷诺数下会降低它。在相同的平均雷诺数下，PCHE 的热性能随着压力的增加而降低，在冷侧三种不同的入口温度中，195 K的入口温度提供了最好的热工性能，而220 K的入口温度是最差的。此外，由于分隔壁中轴向热传导的影响，壁热导率的降低可以提高 PCHE 的热性能。