大 温 差 下 印 刷 电 路 板 式 换 热 器 起 动 过 程建 模 与 实 验

A one-dimensional transient heat transfer model is developed in this study for the starting process of Printed Circuit Heat Exchangers（PCHE）at large temperature difference. The model considers the internal heat conduction process of the solid material of the printed circuit heat exchanger and is able to predict the temperature behavior of both fluid and solid materials. Transient heat exchanger experiments using N₂ as the medium on the printed circuit heat exchanger are conducted. The maximum and minimum temperature of N₂ are 450 K and 103 K，respectively. Comparison of the model prediction results with the experiment results proves the validity of the model. The average deviation of the outlet temperature at the cold side during the starting process is 11. 3 K and the calculation deviations of heat transfer on both sides are within 7%. Furthermore，the model is applied to the calculation and analysis of the spatial distribution and time domain variation characteristics of the operating parameters of the printed circuit heat exchanger. The results indicate that the heat transfer between the cover plate and the core region of the printed circuit heat exchanger is important and cannot be easily ignored in the simulation of the transient process at large temperature difference. The results also show that increasing mass flow rates of fluid at both sides and decreasing the thickness of the cover plate are effective methods to shorten the response time of the starting process. Moreover，in a certain range of the mass flow rate ratio，the product of the Reynolds Number at the inlet of the printed circuit heat exchanger on both sides is an important factor affecting the response time.