三维扩压叶栅非定常流动机理研究的频谱分析

计算了三维直叶栅在不同攻角、不同马赫数下的流动情况,得到流场的非定常解,并进行了频谱分析,对叶栅非定常流动的流场结构和流动机理做了初步的探讨。分析计算结果表明:在来流均匀,定常边界条件下,叶栅内流动仍然表现出强烈的非定常性。分离区和尾迹中的流动,以旋涡的有规律周期性脱落为主要的运动形式。旋涡脱落的频率,随着攻角和马赫数的变化而变化:同马赫数下,攻角越大,频率越低;同攻角下,马赫数越高,频率越高。同时,在同一工况下,旋涡频率沿叶高呈非均匀分布,叶中区域频率相对低,靠近端壁区频率相对高。

Frequency Analysis of Three Dimensional Compressor Cascade Unsteady Flow Mechanism Research

A simulation using unsteady Reynolds-averaged viscous turbulent equations was carried out.The results show that the flow in the separation region and wake region is characterized as periodic or quasi-periodic vortex shedding and the frequency of vortex shedding is varied with incidence and Mach number.At same Mach number,the frequency of vortex shedding decreases with the increase of incidence.Yet,the frequency increases with the increase of Mach number keeping incidence unchanged.In the same situation,the frequency of vortex shedding differs along the span of the cascades.The frequency is lower at the middle of the span than that at the hub.