环形扩压叶栅流动非定常控制方法的PIV研究

利用合成射流发生器对于一台环形扩压叶栅进行了流动主动控制的探索,发现适当的非定常激励方式可以使得环形叶栅的总压损失明显减小。同时利用二维粒子图像测速仪(ParticleImageVelocimetry,简称PIV)测量了扩压叶片绕流流场。获得了不同攻角下,在不同的激励频率和激励强度下,流场结构的变化。结果表明非定常激励可以使叶片绕流流场结构发生明显变化。在合适的非定常激励下,扩压叶片的叶背分离流动得到明显抑制,尾迹漩涡的强度和尾迹宽度均明显减小,流线分布比无非定常激励时更加平滑。实验结果能够与环形叶栅时均总压损失的变化相吻合。对于这一非定常控制方法的作用机理也进行了初步的分析。 

Investigation of Unsteady Flow Control in an Annular Compressor Cascade Using PIV

A synthetic jet generator was used as an active control method to control the flow in an annular compressor cascade.It was found that the total pressure loss of the cascade could be reduced effectively.2D Particle Image Velocimetry(PIV) was used to measure the flow field around the blades.Flow fields were acquired under different incidences,jet frequencies and intensities.It was found that synthetic jet had huge impact on the flow field.With proper jet frequency and intensity,flow separation on the blade suction surface was suppressed evidently,and the blade wake intensity and width were reduced.Streamlines around the blade were smoother.These changes were consistent with the decrease of total pressure loss.The mechanism of this active control method was analyzed.