Flow Control of Vaneless Diffuser Rotating Stall

无叶扩压器旋转失速的流量控制

基本信息

批准号：
02650134
负责人：
TSUJIMOTO Yoshinobu
金额：
$ 0.32万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

In order to elucidate the role of the diffuser wall boundary layers in diffuser rotating stalls, boundary layer suction was applied at various radial locations. The onset flow was increased by the suction owing to the decrease in the main flow rate, showing that the current explanation attributing to the reverse flow is not adequate.A 2-D inviscid, nonlinear diffuser flow anaysis was made. At smaller flow rates, flow patterns similar to that observed in experiments appeared when the vorticity from the inpeller constitutes a certain pattern. However, the onset condition is too severe compared with experiments and the instability did not occur when the effects of skin friction on the diffuser wall was taken into account. Thus, the simulated instability looks to be different from those observed experimentally.Discussions on the energy balance of rotating stall were made from the results of an active control of the rotating stall. The control was made by introducing a fluctuating flow at the diffuser inlet, which is in a certain phase relation with the rotating stall. Discrete frequency component due to rotating, stall completely disappeared in the whole diffuser indicating that the control is not due to a mere linear superposition of the disturbance but the rotation stall flow itself is changed by the addition of the disturbance. The energy transferred to the diffuser flow by the displacement effect of the fluctuating flow was related with the controlled rotating stall amplitude. It was shown that the amplitude decreased when the energy is negative. From this result, the quantitative discussion was made as to the relation between the amplitude and the energy balance of vaneless diffuser rotating stall.

为了阐明扩散器壁边界层在扩散器旋转摊位中的作用，在各种径向位置应用边界层抽吸。由于主要流速的减少，吸入增加了开始流动，这表明归因于反向流的当前解释不足。2-D Inviscid，非线性扩散器流量anaysis被做出了。在较小的流速下，当来自Inpeller的涡度构成某种模式时，流量模式与实验中观察到的流动模式相似。但是，与实验相比，开始情况太严重了，当考虑到皮肤摩擦对扩散壁的影响时，就不会发生不稳定性。因此，模拟的不稳定性看起来与实验观察到的不稳定性不同。从旋转失速的旋转摊位的能量平衡上进行了识别。控制是通过在扩散器入口处引入波动流的，该流量与旋转失速处在一定相位的关系中。由于旋转而导致的离散频率分量，失速在整个扩散器中完全消失，表明控制并不是由于干扰的线性叠加而引起的，而是通过添加干扰而改变了旋转失速流本身。通过波动流的位移效应传递到扩散器流量的能量与受控的旋转失速振幅有关。结果表明，当能量为负时振幅下降。从这个结果，进行了定量讨论，就振幅和无食子旋转失速的振幅平衡与能量平衡之间的关系进行了讨论。