Exploring flow mechanism of effect of circumferential grooved casing treatment on performance of subsonic axial flow compressor

Aim: To our knowledge, existing papers^[3,5] offer only very limited knowledge on the underlying flow mechanism of the effect of circumferential grooved casing treatment on the performance of axial flow compressor. We now explore further the underlying mechanism of the effect of circumferential grooved casing treatment on the performance of a subsonic axial flow compressor. In the full paper, we explain our exploration in same detail. In this abstract, we just add some pertinent remarks to listing the three topics of explanation. The first topic is: NWPU special experimental set-up for single stage axial flow compressor and our grooved casing configuration. The second topic is: Numerical simulation method employed. The third topic is: The analysis of numerical simulation results. Its two subtopics are: The analysis of overall performance (subtopic 3.1) and the analysis of the underlying mechanism for the augmentation of the stability margin with circumferential grooved casing (subtopic 3.2). In subtopic 3.1, the calculated overall performance lines, given in Fig. 3 in the full paper, show good agreement with the experimental results. In subtopic 3.2, Figs. 4 through 8 show the results of the analysis of the underlying mechanism; on the basis of the analysis, the underlying mechanism consists of: (1) The casing treatment weakens blade tip load and consequently reduces the driving power of tip leakage flow, thus restraining the development and decreasing the intensity of tip leakage vortex; (2) Circumferential grooves have the ability to pump or blow the low energy flux near end wall and the action of blowing or bleeding can suppress significantly the blockage of blade passage.