真空羽流试验设备的负压液氮系统设计

真空羽流试验设备用于发动机真空羽流效应试验研究,同时兼顾卫星等热真空试验,对液氮系统有特殊要求。针对低至70 K液氮温度需求,设计一种全新的负压液氮系统,即利用液氮在负压下具有比常压液氮更低的饱和温度,来获得比常压液氮系统更低的液氮温度。该负压液氮系统主要由液氮输送子系统、常压过冷器子系统、负压抽气子系统、液氮泵子系统、热沉子系统及排放子系统组成,其中常压过冷器子系统和负压抽气子系统构成"负压过冷器",具有常压过冷器功能,供液温度可调,可为热沉提供70~77 K液氮制冷,满足发动机羽流及卫星热真空试验需求。

Design of negative pressure liquid nitrogen system of vacuum plume experimental facility

The plume effect experimental system(PES) is used for the plume effect test of rocket engines and the vacuum heat tests of satellites, with special requirements for the liquid nitrogen system. A new negative system is designed for the liquid nitrogen temperature as low as 70 K. In this system, the liquid nitrogen at a negative pressure is used to have a lower saturation temperature than the atmospheric pressure nitrogen, and to obtain a lower liquid nitrogen temperature than the conventional liquid nitrogen subsystems. The negative pressure liquid nitrogen system consists of the liquid nitrogen delivery subsystem, the atmospheric subcooler subsystem, the negative pressure pumping subsystem, the liquid nitrogen pump subsystem, the heat sink subsystem and the discharge subsystem, where the atmospheric subcooler subsystem and the negative pressure pumping subsystem are combined to serve as the negative pressure subcooler. With the atmospheric subcooler, the negative pressure subcooler can adjust the temperature of the feeding fluid and provide the heat sink with 70-77 K liquid nitrogen for refrigeration, to meet the demand of the engine plume experiment and the thermal vacuum test of satellites.