脉冲射流控制弯曲扩压管道流动分离的特点

Characteristic of controlling flow separation in divergent curved channels by pulsed jet

结合弯曲扩压通道的脉冲射流总体控制规律,开展了不同射流频率下通道内流场的稳定及动态特性分析.研究结果表明:定常射流控制状态下,流场内沿径向不同位置流动特性的变化幅度基本相同,定常射流通过压制通道内复杂流动现象达到整体线性地改变通道内流场特性的效果;而在合理脉冲射流控制状态下,脉冲射流对流场的影响主要是通过改变分离涡的脉动时空特性,沿径向逐步增强对流场的影响,从而使得主流区内总压损失降低幅度最为明显,此时扩压通道内占主导地位分离涡的周期性特征有了明显的改善,流场拟序结构更为有序.

Combined with the pulsed jet overall control ruler of divergent curved channels, the steady and unsteady characteristics of flow fields in channel under different frequency states were an- alysed. Results show that the flow characteristics change amplitude is similar along the radial direc- tion under steady control state, and the influence of steady jet suppresses the complex flow phenom- enon and linearly changes the flow characteristic of the flow field. Under suitable pulsed jet control state, the influence of pulsed jet on the flow field is presented by changing the fluctuation time-space characteristic of separation vortex, so that the influence amplitude increases along the radial direc- tion, and the decreased magnitude of total pressure loss in the mainstream region is more obvious; meanwhile, the periodic characteristic of the dominant separation vortex is improved significantly, and the flow coherent structure is more orderly.