Instability Inception of a Single Rotor Embedded in a Transonic Stage with Partial Surge Inception

Partial surge is a type of instability inception discovered in our previous studies.It has been confirmed that partial surge is localized in the blade hub region,and the flow oscillation it caused will lead to the stall cells in the rotor tip.While since all information about partial surge is obtained from the compressor stage experiments,what will happen to the stall process after the stators are removed is also an issue that worth investigating.So,in this paper,a series of experiments are carried out on the single rotor embedded in the transonic compressor stage with partial surge inception.First,the experimental results under uniform inlet conditions show that,although partial surge appears at high rotor speed in the stage case,it does not occur at any speed in the single rotor case.Then,it is found by numerical simulation that the absence of partial surge may be due to the insufficient rotor hub loading,so an experiment with increased hub loading is carried out,but still fails to trigger partial surge.Finally,the reason why partial surge doesn’t occur in the single rotor is discussed.From these results,it can be concluded that partial surge cannot occur in the single rotor case,and the large-scale comer separation in the stator hub is considered to play an important role in the formation of partial surge.