民用飞机进气道低速大迎角性能风洞实验和数值计算分析

Wind Tunnel Test and Numerical Study on Civil Aircraft Inlet Performance under Low Speed and High Angle of Attack Condition

关键词:  总压畸变  进气道  短舱  风洞实验  流动分离  失速  数值计算

Key words:  Total pressure distortion  Inlet  Nacelle  Wind tunnel test  Flow separation  Stall  Numerical simulation

摘要:

为了研究民用飞机进气道在起飞低速大迎角状态下的流场特征和性能，对设计马赫数为0.785的进气道进行了风洞实验和数值计算，来流马赫数为0.2，迎角变化为0°~25°，流量系数为0.29~2.07。研究结果表明：在起飞工况条件下，进气道正常工作迎角可达到25°；在起飞单发失效工况条件下，进气道外罩上流动分离迎角在13°~16°；在大迎角工作条件下内流未产生分离时，出口气流畸变受发动机流量变化影响较小。通过研究结果分析了进气道在低速大迎角状态下的流场特征及其随迎角、流量的变化规律。数值计算和风洞实验结果的对比表明，在没有流动分离时两者基本一致；但是对于外流分离迎角的预测，两者有3°差异，表明风洞实验依然是考核进气道性能的必要手段。

Abstract:

In order to investigate the flow character and performance of civil aircraft inlet under low speed and high angle of attack condition， wind tunnel test and numerical simulation are conducted for an inlet with design Mach number of 0.785， under the condition of coming flow Mach number 0.2， angle of attack from 0°~25°， and mass flow ratio from 0.29~2.07. The results show that， under take off condition， the inlet could work under angle of attack up to 25°.Under take off condition with one engine inoperative， the inlet external flow separation may occur at angle of attack 13°~16°.Under high angle of attack condition without flow separation， mass flow ratio has limited influence on the inlet distortion. Based on the results， the inlet flow character under low speed and high angle of attack condition， and its variation with angle of attack or mass flow ratio is analyzed. Comparison between numerical simulation and wind tunnel test results show that， the two could coincide with each other when no flow separation occurred，however， the difference of external flow separation angle could be up to 3°， suggesting wind tunnel test is still necessary to validate the inlet performance.