整机条件下涡扇发动机部件特征参数辨识

为解决整机条件下难于直接获得部件全部特征参数的问题,在计算发动机部件特征参数对整机性能敏感度的基础上,利用条件数分析参数之间的相关性最终确定可修正参数数量.这样即可构造工程上可解的辨识问题,并通过最小二乘法求解.仿真计算结果显示:高压压气机效率为0.982与初设值0.98一致,说明该方法从理论上是可行的.从具体实例的辨识结果来看,有压气机后温度测试时部件效率降低量值符合实际结果;无压气机后温度测试时高压压气机效率较设计状态偏高12.7%,不符合实际发动机工作情况.显然辨识问题是病态的,为此可修正参数不应超过6个. 

Identification of component characteristic parameter for whole turbofan engine

In order to solve the difficulty to directly obtain all characteristic parameters of the components in the whole turbofan engine, it was determined ultimately that the number of corrected parameters by using the condition number of the correlations between parameters, on the basis of sensitivity calculation of the characteristic parameters of engine components to engine performance. Thus, the identification problem could be solved in engineering by the least square method. The simulation results show the efficiency of high compressor was 0.982 consistent with initial value of 0.98 , indicating that the method is theoretically feasible. From the identification results of concrete example, the efficiency value of components were in accord with the actual results with the compressor temperature test; in contrast, the efficiency value compared with the design state was higher than 12.7% , which did not match the actual engine operating conditions. Clearly, the identification problem was ill-posed, so parameters can be amend should not exceed 6.