A sufficient understanding of the stall behavior is crucial to improve the stability of a compressor. The stall development process and its sensitive locations in a centrifugal compressor with a volute and a vaneless diffuser are investigated by unsteady simulations and an experiment in this study. During the throttling process, two stall stages are observed: stall I and stall II. During stall I, the mass flow rate has a small fluctuation and a local stall occurs at the impeller inlet. The local stall region is caused by a local spillage flow due to the tip leakage vortex, which results in a static pressure fluctuate at low-frequency and a blade loading reduction in the main blade fore part. During stall II, the mass flow rate fluctuates violently and reduces dramatically, accompanied by a significant reduction in the pressure ratio and efficiency in the experiment. Stall II is the whole-annulus stall caused by the large reverse flow at the impeller inlet region, leading to a large low-frequency signal and a large reduction in the blade loading at the main and splitter blade fore parts. However, stall II also has an effect on the impeller downstream and the diffuser. Due to the influence of the volute, stall I needs to locally extend to a certain size at the impeller leading edge; stall II then appears and causes an abrupt variation in the compressor flow field.

充分了解失速行为对于提高压缩机的稳定性至关重要。通过非稳态模拟和实验研究了带有蜗壳和无叶扩压器的离心压缩机中失速发展过程及其敏感位置。在节流过程中，观察到两个失速阶段：失速I和失速II。在失速I期间，质量流率波动较小，并且在叶轮入口处发生局部失速。局部失速区域是由于尖端泄漏涡流引起的局部溢出流而引起的，这导致静压力在低频下波动并且主叶片前部中的叶片载荷减小。在失速II期间，质量流率剧烈波动并急剧下降，伴随着实验中压力比和效率的显着降低。失速II是整个叶轮失速，是由于叶轮入口区域处的大量逆流引起的，从而导致了较大的低频信号并大大降低了主叶片和分流叶片前部叶片的负荷。但是，失速II对下游叶轮和扩散器也有影响。由于蜗壳的影响，失速I需要在叶轮前缘局部扩展到一定尺寸；然后出现失速II，并导致压缩机流场突然变化。失速II对叶轮下游和扩散器也有影响。由于蜗壳的影响，失速I需要在叶轮前缘局部扩展到一定尺寸；然后出现失速II，并导致压缩机流场突然变化。失速II对叶轮下游和扩散器也有影响。由于蜗壳的影响，失速I需要在叶轮前缘局部扩展到一定尺寸；然后出现失速II，并导致压缩机流场突然变化。