Numerical investigation of flow maldistribution in inlet header of printed circuit heat exchanger

Printed Circuit Heat Exchanger (PCHE) can be used as the heat transfer device for high-temperature molten salt reactors due to its high efficiency and compact structure. However, PCHE is a typical multi-channel heat exchanger. The flow distribution in the PCHE channels is significantly influenced by geometric design and operating conditions. Flow maldistribution among channels can lead to temperature non-uniformity, which adversely impacts heat transfer performance and overall system efficiency. In this study, numerical simulation is used to investigate the effect of inlet header structure on flow distribution in the straight-channel PCHE. A modified inlet header with a flow homogenizer is designed. The influence of geometric parameters on flow maldistribution among channels is systematically analysed, such as header width, inlet pipe diameter, and the arrangement of perforations on the flow homogenizer. The results indicate that the header structure has a significant impact on the uniformity of flow distribution. With modified geometric parameters, the inlet header with flow homogenizer reduced the maximum deviation in flow distribution to 1.7%. The result meets the requirements of engineering design and provides an important reference for the design of molten salt reactors.