某民用涡扇发动机飞行包线内吸雨量计算分析

分析吸雨对发动机工作性能的影响,首要的是确定能被发动机吸入的雨量。通过综合考虑适航规章要求的大气雨水分布、环境温度、飞行速度、发动机功率和聚集效应对发动机吸雨的影响,结合完整的推力调节计划,计算分析了某民用大涵道比涡扇发动机在不同推力等级下全飞行包线内风扇进口水气比(WAR)。结果表明:在同一马赫数下,风扇进口水气比在6 100m处达到最大;在该高度以下,水气比随着高度的增加而增大;在该高度以上,水气比随着高度的增加而减小;飞行马赫数越大、环境温度越高,水气比也越大;并且标准天空中慢车推力下的风扇进口水气比最大可达到7.38%。该计算方法可为民用涡扇发动机吸雨适航取证的关键点分析提供参考。

Calculation and analysis of fan inlet rain ingestion of a civil turbofan engine throughout the flight envelope

To evaluate the influence of rain ingestion on the performance of an aircraft engine,the amount of rain ingested into the engine should be determined first.In this paper,the effects of liquid water concentration profiles defined by China Civil Aviation Regulations,environment temperature,flight speed,engine power,and scoop factor on water ingestion of engine,combined the full power management schedules,the fan inlet water air ratio (WAR) throughout a civil turbofan engine's operating envelope at different thrust levels is calculated and analysed.The results at all power levels show that at any constant Mach number,fan inlet water air ratio increases with altitude until it peaks at 6 100 m.Above 6 100 m,WAR decreases with the increase of altitude.Furthermore,the higher the Mach number and the ambient temperature,the larger the WAR.For flight idle on a standard day,the maximum WAR can reach as high as 7.38％.The calculating and analyzing method presented in this paper can provide the inlet boundary condition for analysis of rain ingestion critical point in engine airworthiness compliance test.