连续式跨声速风洞降温系统液氮存储装置的设计与调试

低温运行是提高风洞实验雷诺数的有效途径。采用喷洒液氮的方式，NF-6风洞建成了国内第一套适用于连续式跨声速风洞的降温系统。介绍了NF-6风洞降温系统的总体方案和主要技术指标，重点介绍其液氮存储装置的结构和技术原理，给出了静态和通气运行调试结果。测试结果表明:提出的液氮需求量计算方法正确，为储罐容积估算提供了理论依据；液氮存储装置设计合理，液氮加注通畅平稳，自增压系统工作正常，绝热性满足低温液氮存储要求；储罐的液氮日蒸发率为0.044%，远低于设计指标；液氮存储装置与降温系统整体匹配良好、工作稳定，总温、总压、马赫数以及运行时间等关键指标达到设计要求。

Design and debugging of the liquid nitrogen storage device in continuous transonic wind tunnel cooling system

The low temperature operation is an effective way to improve the Reynolds number in wind tunnel experiments. By means of liquid nitrogen injection, the first cooling system for the NF-6 continuous transonic wind tunnel has been built in China. The overall scheme and main technical indicators of the liquid nitrogen injection cooling system in NF-6 wind tunnel are introduced. The structure and technical principles of the liquid nitrogen storage device of the cooling system are expounded and the static and dynamic debugging results are presented. Test results indicate that our calculation method of the liquid nitrogen consumption is correct and it provides theoretical references for volume estimation of the liquid nitrogen tank. The scheme design of the liquid nitrogen storage device is reasonable and the liquid nitrogen injecting process is smooth and unimpeded. Meanwhile, the self-pressurized system of the liquid nitrogen storage device is working well and the heat-insulating properties of the liquid nitrogen tank can meet the requirements of the cryogenic liquid nitrogen storage.The daily evaporation rate of the liquid nitrogen in the tank is 0.044%, far lower than the designed index.The liquid nitrogen storage device has a good match with the whole cooling system. Throughout the debugging process, the key indicators such as the total temperature, total pressure, Mach number and running time have reached design requirements and excellent performance was achieved.