组合临界流文丘里喷嘴空气流量测量方法高空舱应用分析

为满足发动机高空试验低流速进气条件下空气流量精确测量,减小进气导管气流附面层影响,弱化空气流量测量与被试发动机相关性。分析了单件/组合临界流文丘里喷嘴的工作特性,给出了组合临界流文丘里喷嘴(ACFVN)空气流量计算方法,依据给定试验发动机和高空舱尺寸设计了临界流文丘里喷嘴组合结构,得到了组合临界流文丘里喷嘴在高空舱应用的控制方法和测试布局。采用小尺寸喷嘴对组合喷嘴设计和应用方法进行了验证,结果表明:采用打开/关闭喷嘴数量和调节进气压力两种组合方式在高空舱内应用方法可行,测试布局满足测量要求,下游发动机进口截面气流紊流度优于0.3%,满足发动机高空模拟试验要求。 

Analysis of method of air mass flow measurement based on array of critical flow Venturi nozzle in high-altitude simulation facility

In order to meet the accurate measurement of air flow under the low flow intake conditions of the engine high-altitude test, reduce the influence of the air flow surface layer in the intake duct, and weaken the correlation between the air flow measurement and the tested engine, the working characteristics of the single piece/combined critical flow Venturi nozzle (CFVN) were analyzed, and the calculation method of the air flow of the array of critical flow Venturi nozzle (ACFVN) was expounded. The calculation method of combined CFVN was also given. The combination structure was designed according to the given test engine and the size of the high-altitude cabin. The control method and test layout of the combined CFVN in high-altitude cabin were obtained. The design and application methods of the combined nozzles were verified by small-sized nozzles. The results show that the method of opening and closing the nozzles and adjusting the intake pressure could be applied in the high-altitude cabin, the test layout meets the measurement requirements, and the Turbulence of engine intake flow is better than 0.3%, meeting the requirements of engine high altitude simulation test.