A numerical investigation is carried out on the pressure drop and heat transfer performance of a compact U-shaped-tube bundle heat exchanger in a rectangular channel. The compact exchanger is modeled as a porous matrix. By using dual meshes method, the external flow and the internal flow are allowed to be solved simultaneously and the two flows be coupled only through heat transfer at the heat exchanger core. An experiment is conducted to validate this numerical method. It is identified that the current numerical approach is capable of providing an appropriate prediction in the pressure drop and heat transfer efficiency of heat exchanger. Interestingly, the distributor-collector arrangement is found to have an obvious influence on the heat transfer efficiency for this specific U-shaped-tube bundle heat exchanger. By compassion, the reasonable arrangement of distributor-collector is that the upper main tube is used as the distributor tube and the lower main tube is used as the collector, which could achieve an approximate 15% increase (according to the experimental results) or 10% increase (according to the numerical predictions) in the heat transfer efficiency, when compared to the opposite arrangement.

中文翻译：

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双网法结合多孔介质模型的U形管束式换热器的数值研究

对矩形通道中紧凑型U形管束式换热器的压降和传热性能进行了数值研究。紧凑型交换器被建模为多孔基质。通过使用双网格方法，可以同时求解外部流和内部流，并且仅通过热交换器核心处的传热将两个流耦合。进行实验以验证该数值方法。可以确定，当前的数值方法能够对热交换器的压降和传热效率提供适当的预测。有趣的是，对于这种特定的U形管束式热交换器，发现分配器-收集器布置对传热效率有明显的影响。出于同情，