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为了分析一种运用于压气机内分离流控制的无源脉冲射流控制技术的特点,基于弯曲扩压通道试验模型进行了脉冲射流控制的试验和数值模拟研究,结果均表明当射流频率接近通道内分离涡主频时控制效果最为明显;引入了本征正交分解(POD)技术对无控状态下通道内流场结构进行分析,得到了POD各阶模态的流动结构特征。在此基础上对比分析了定常及非定常控制特点,结果表明:非定常控制方式主要是重分配各阶模态之间的能量,有选择性地强化或削弱某阶模态;定常射流控制则是整体削弱高阶模态,压制通道内复杂流动现象;合理地构建脉冲射流可使能量从高阶模态向平均流模态进行转移,能量的转移通过空间流场结构的重构和模态时间演化特性的序化实现。最后针对POD分析结果进行了验证性试验研究,试验结果部分反映了时空特性的变化规律,提升了POD分析结果的可信度。
In order to analyze the characteristics of a passive pulse jet control technology used in the separation flow control of a compressor, the experimental and numerical simulations of pulse jet control based on the bending diffuser channel test model are carried out. The results show that when the jet frequency is close to the channel The control effect is the most obvious when the dominant frequency of the separation vortex is adopted. The structure of the flow field in the channel under uncontrolled state is introduced by the introduction of the technique of intrinsic orthogonal decomposition (POD), and the flow structural characteristics of each mode of the POD are obtained. On this basis, the characteristics of steady and unsteady control are contrasted and analyzed. The results show that the unsteady control mode mainly reallocates energy between different modes and selectively strengthens or weakens certain modes. The steady jet control Is to weaken the high modes as a whole, and suppress the complex flow phenomenon in the channel. The reasonable construction of the pulsed jet can transfer the energy from the high-order mode to the mean-flow mode. The energy transfer is through the reconstruction of the spatial flow field structure and the evolution of the modal time Order to achieve. At last, a confirmatory experimental study on the results of POD analysis is carried out. The experimental results reflect the variation of spatio-temporal characteristics and enhance the credibility of POD analysis results.