蜗壳非轴对称性对离心压缩机内部非定常流动影响的数值研究

Numerical Investigations on Influence of Volute Non-Axisymmetry on Unsteady Flow in Centrifugal Compressor

本文采用非定常数值模拟方法研究了蜗壳几何非轴对称性对离心压缩机内部非定常流场的影响。结果表明:流场的非定常波动主要受叶轮影响。远离蜗壳设计工况时,蜗壳非对称性的影响可传播至叶轮主叶片前缘。蜗壳非对称性对扩压器叶片压力面瞬时压力的影响在小流量和设计流量工况下主要体现叶轮主叶片与分流叶片通过频率的影响,而在大流量工况下叶轮主轴旋转频率也占一定比重。叶轮主叶片压力面的非定常压力波动主要受叶轮主轴旋转频率及其倍频与扩压器叶片通过频率及其倍频的影响。

The influence of volute non-axisymmetry on the unsteady flow in a centrifugal compressor is investigated by the unsteady numerical simulation. The results indicate that, the flow unsteady fluctuation in the centrifugal compressor is dominated by the impeller. The influence of volute non-axisymmetry can be propagated to the leading edge of impeller when the volute is operated away from its design condition. The influence of the non-axisymmetric structure of volute on the instantaneous pressure at the pressure surface of diffuser vane is mainly on the main and splitter blades passing frequency at the low and design flow rates, while the im- peller shaft rotating frequency also plays an important role under the large flow rate condition. The pressure fluctuation on the pressure surface of impeller main blade is mainly affected by the impeller shaft rotation frequency, the diffuser blade passing frequency and their multiple frequencies.