S型泡沫金属管翅式换热器的设计与实验研究

为解决航空发动机部件热防护以及热管理问题，针对CCA(cooled cooling air)技术，采用高孔隙率泡沫金属替代传统管翅式换热器金属翅片，设计一种轻质、高效、紧凑的小尺寸S型泡沫金属管翅式换热器。换热器芯体为3D打印的钛合金制作，重129 g，由S型管束以及泡沫金属翅片组成，翅片安装在管束直管段处。流动传热实验模拟航空发动机机匣外部的空-油换热器，冷侧为水，热侧为高温空气，测定两侧流体的流量、进出口温度及压力。结果表明：泡沫金属作为换热器的翅片，传热系数增大43.94%、换热量提升21.7%、综合换热性能增加25.43%，功重比平均提升17.26%，可达14.61 kW/kg。这说明泡沫金属能够提升换热器的整体性能，可用于未来航空发动机相似结构换热器的设计。

Design and experimental study of S-type foam metal tube-fin heat exchanger

In order to solve the problem of thermal protection and thermal management of aero-engine components, for CCA (cooled cooling air) technology, high-porosity foam metal was used to replace the metal fins of traditional tube-fin heat exchangers, and a lightweight, efficient, and small size S-type foam metal tube-fin heat exchanger was designed. The heat exchanger core made of 3D printed titanium alloy, with weight of 129 g, was composed of S-shaped tube bundles and foamed metal fins. The fins were installed at the straight pipe section of the tube bundle. The flow heat transfer experiment simulated the air-oil heat exchanger outside the casing of an aero engine, with water on the cold side and high temperature air on the hot side. The flow rate, inlet and outlet temperature and pressure of the fluid on both sides were measured. The results showed that: for the fin of the heat exchanger, the heat transfer coefficient increased by 43.94%, the heat transfer increased by 21.7%, the comprehensive heat transfer performance increased by 25.43%, and the power-to-weight ratio increased by 17.26% on average, reaching 14.61 kW/kg. This showed that the metal foam can improve the overall performance of the heat exchanger and can be used in the design of heat exchangers with similar structures for future aero-engines.