To examine the benefit of the pressure drop effect in a heat exchanger, we designed and tested the heat exchanger with significant pressure loss in the temperature range between 4.2 K and 1.8 K. The numerical investigation was also carried out to elucidate the effect of continuous pressure drop, namely the distributed JT effect, in the heat exchanger. We verified the numerical simulation model by comparing the calculation results of the heat capacity rates in two-phase flow conditions with the theoretical values obtained by Clausius-Clapeyron relation. The maximum errors are obtained as 18.4% and 17.0% in two experimental cases, respectively. The performance indicator is defined to explicitly represent the distributed JT effect, which is derived as the ratio of the actual enthalpy change by pressure drop to the maximum potential enthalpy change by pressure drop. It is evaluated as 59% and 67% in the two experimental cases, respectively. The relatively small performance indicators obtained in our experiments are caused by the small heat transfer area of the heat exchanger. To increase the performance indicator of the heat exchanger, we propose an advanced heat exchanger with sufficient pressure drop and increased heat transfer area.

为了检查换热器中压降效应的好处，我们设计并测试了在 4.2 K 和 1.8 K 之间的温度范围内具有显着压力损失的换热器。还进行了数值研究以阐明连续压力的影响下降，即分布式 JT 效应，在热交换器中。我们通过比较两相流条件下的热容率计算结果与克劳修斯-克拉珀龙关系式获得的理论值来验证数值模拟模型。在两个实验案例中，最大误差分别为 18.4% 和 17.0%。性能指标被定义为明确表示分布式 JT 效果，它是由压降引起的实际焓变与压降引起的最大潜在焓变之比得出的。在两个实验案例中，它分别被评估为 59% 和 67%。我们实验中得到的性能指标比较小，是由于换热器的传热面积小造成的。为了提高换热器的性能指标，我们提出了一种具有足够压降和增加传热面积的先进换热器。