| With the demands of high performance aircraft engine highlight, the development of high load compressor is imperative. Unsteady internal flow separation not only impacts the performance of high-load compressor, but also affects the stability of the whole compressor. The active flow control research still can’t explain the unsteady flow control mechanism clearly, and the effect of active control method still needs to be improved, moreover,it’s difficult for actuator to fit on the compressor working on a wide range.In this paper, the dual-pulse jets technology was studied and applied in plane cascade. The main work and conclusions are as follows:1、Two jets holes were setted in the separation point along the flow direction, through comparing the single and dual-pulse jets control effect, moreover achieve dual-pulse jets control mechanism based on the vorticity nephogram and flow fluctuation characteristics, correlation coefficient analysis etc..2、The jet frequency and phase difference were investigated, getting out the optimal control effect. Though CFD simulation, the optimal frequency is 1 and the optimal phase difference is 0 degree. At the same time, local wave interference influencing phase difference was also verified.3、Developing FFT-POD method to analyze the each scale vortex structure movement of unsteady flow field, and getting out that the dominant frequency of the every time modal frequency coefficient approximate linear increase. Most of the flow energy is in the resonance state, and the main modal are the first modal,standing for average flow, the second, third modal standing for large scale vortex structure, there is attenuation in the resonance energy when transferring to small scale vortex structure, and resonance cannot dominate all the changing rule of the vortex system structure.4、The energy spectrum difference points out that unsteady excitation cause fluid infinitesimal rotation motion strengthened and the straight flow weakened. This is caused by flow field energy exchange. At the same time more kinetic energy is concentrated in the large scale vortex structure.5、The effect laws that dual-pulse jets work to the diffuser is similar to the cascade, and the dual-pulse jets control effectiveness and the rationality of the interpretation of parameters were verified, besides, the results show that the control effect of dual-pulse jets won’t strongly rely on jet velocity. |
