基于试车数据统计的振动限制值确定方法

统计了某型液体火箭发动机涡轮泵27次地面试车振动数据和某型涡扇发动机28次台架试车振动数据,发现一次试车时间序列的振动特征参数随时间的波动反映了随机误差的变化,符合正态分布;不同台份发动机试车振动参数幅值的波动是发动机健康状态和试验误差共同作用的结果,不遵循正态分布规律,F分布是其分布的重要形式。在此基础上,研究了基于"概率相等法"和"3σ方法"原理的两种发动机振动限制值的确定方法。通过两种方法计算结果的相互验证,以及计算结果和工程实践的对比,说明确定振动限制值方法的正确性和实用性。

Estimating vibration limit value based on statistics for engine testing data

Through analyzing twenty seven vibration data in ground fire testing of a liquid propellant rocket engine,and twenty eight vibration data of a turbofan engine,we find that on one hand the characteristic parameters are submitted to Gaussian distribution in a time series of ground fire testing,and on the other hand the characteristic parameters of different time series are more likely submitted to F distribution rather than Gaussian distribution.Based on the above work,we study two methods to estimate the vibration limit value of the engine respectively.One method is based on the probability equality principle,and the other adopts 3σ principle.We compare the above two methods with the same vibration data.Through analyzing the differences of the processing results,the advantages and disadvantages of the two algorithms are pointed out.In addition,the processing results are further compared with vibration limit value used in engineering practice,and the results demonstrate the effectiveness and correctness of the proposed methods.