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首先针对发动机空气预冷系统的特点,将现有的预冷机制分为四种类型,包括燃料预冷、质量喷注预压缩冷却、燃料预冷和质量喷注预压缩冷却组合预冷以及其他流体预冷,并分别介绍了每种预冷机制的代表性发动机循环以及技术特点。调研发现,微小通道结构的预冷器具有很高的散热能力和紧凑度,优势显著。英国Skylon空天飞机的预冷却组合循环发动机(SABRE)其微通道结构预冷器具有极高换热能力。对SABRE的预冷器及相关研究进行详细分析,强调微小通道强化换热对提高发动机性能的重要作用。通过对微小通道中单相气态流动换热研究的调研发现,微尺度流动传热机理仍存在诸多分歧,理论发展不完善,需要深入开展微小通道强化传热研究,尤其对于高速高内外温差条件下微小尺度复杂结构空间内流动传热机理需要深入探索。
First of all, based on the characteristics of engine air precooling system, the existing precooling mechanism is divided into four types, including precooling of fuel, mass injection precompression cooling, precooling of fuel precooling and mass injection precompression cooling, and other Fluid precooling, and introduced the representative of each precooling engine cycle and technical characteristics. The survey found that the micro-channel structure of the precooler with high cooling capacity and compactness, the advantage is obvious. Pre-cooling Combined Cycle Engines (SABER) for Skylon spacecraft in the UK have micro-channel precoolers with extremely high heat transfer capability. The SABER precooler and related research are analyzed in detail, emphasizing the important role of micro-channel heat transfer enhancement to improve engine performance. Through the investigation of single-phase heat transfer in micro-channel, it is found that there are still many disagreements on the mechanism of heat transfer in micro-scale. The theoretical development is not perfect, so it is necessary to carry out the research of micro-channel heat transfer enhancement. Especially for high temperature and high temperature difference The mechanism of the flow and heat transfer in the micro-scale complex structure space needs further exploration.