高速风洞连续变速压颤振试验技术研究

针对高速暂冲式风洞阶梯变速压颤振试验用时长、耗气量大和试验模型有效使用寿命短等缺点,开展了高速暂冲式风洞连续变速压颤振试验技术研究,解决了定 Ma 数连续变速压流场控制技术与连续变速压工况下的颤振试验数据处理技术等难题。具体技术措施是:在2.4m×2.4m 暂冲式跨声速风洞中设计了基于运动函数的定Ma 数线性变总压控制策略,使 Ma 数控制精度达到了0.005以内且速压无超调,实现了流场控制目标;采用 Pick-Hold 方法构建颤振边界的亚临界预测判据,并根据预测判据近似于正态分布的特点,基于数理统计的参数估计法来减小预测判据的散布度,从而提高颤振边界亚临界预测的准确性。风洞验证试验结果表明,该试验技术达到了工程实用化水平,不仅能够取得与阶梯变速压颤振试验技术一致的结果,还能极大地节省耗气量,经济效益显著。

Research on flutter test technology of continuously adjusting dynamical pressure in high-speed wind tunnel

According to the defects shown in the flutter tests of stepped adjusting dynamical pressure in high speed intermittent wind tunnel,such as:long testing time,high gas consump-tion,and short acceptable life of testing models,researches on flutter test technology of continu-ously adjusting dynamical pressure in high-speed intermittent wind tunnels are conducted.Tech-nical problems of flutter test data processing and wind tunnel flow controlling have mainly been solved.The specific approaches are:in the 2.4m×2.4m blow off transonic wind tunnel,fixed Mach number and linear varying total pressure controlling strategies based on movement function are presented,and thus the flow controlling goal of fixed Mach number continuously adjusting dynamical pressure is achieved.The controlling uncertainty of Mach number reaches less than 0.005 without deviation of dynamical pressure.The Pick-Hold method is adopted to set up the subcritical prediction criterion in flutter boundary;according to the characteristic that the recipro-cal of predicting criterion is close to the normal distribution,a parameter estimation method based on the mathematical statistics theory can be used to reduce the diffusive sampling of the prediction criterion and then the accuracy of the subcritical prediction of flutter boundary can be increased.The results of wind tunnel verification test show that the flutter test results of contin-uously adjusting dynamical pressure is in consistent to that of stepped adjusting dynamical pres-sure,and the test technology has reached engineering practical levels;besides,the gas consump-tion is greatly reduced by using flutter test technology of continuously adjusting dynamical pres-sure,and thus it also has good economic benefits.