Tip clearance model for transient state of multi-stage compressor based on transient state spectrum blocks

<bold> </bold>For the complex response of compressor tip clearance in a transient state, a multi-stage compressor tip clearance model for transient state based on system identification was developed to efficiently and accurately predict the tip clearance. First, the tip clearance data was calculated by finite element model and the data was verified through experiment, so the rotor and stator deformation data of finite element analysis and engine performance data were used for the sample output and input separately. Then the transient state spectrum blocks for the tip clearance analysis were established from the usage of engine. And different transient state spectrum blocks were identified one by one to determine the order ranges of the model. Then the parameters of the model were gained through combining the spectrum block into typical complex transient state processes. Finally, the established tip clearance model was validated by a complete transient state spectrum. It can be seen that the mean accuracy of the established blade tip clearance model is over 95% which can satisfy the requirements of clearance prediction, and the calculation time is on the order of seconds, that can be used for monitoring the clearance between the rotor and stator of multi-stage compressors, as well as for tip clearance inspection before test or flight, to ensure engine safety.