Experiment of dynamic evolution characteristics of stall cells

The throttling characteristics of a single-stage low-speed axial compressor were experimently investigated. Dynamic pressure signals were measured during the throttling process by dynamic pressure sensors in circumference. In order to analyze the dynamic evolution characteristics of stall cells during the throttling process, time domain analysis and frequency domain analysis were conducted combined with polar coordinate visualization. The results indicate that stall precursor type is modal wave and the frequency of modal wave is about 40% rotor rotation frequency; the compressor generates two stall cells at 349.5 r in circumference at the early stage of stall, and two stall cells merge into one at 360 r; one stall cell begins to split as the compressor runs into deep stall and splits into two stall cells at 410 r; two stall cells merge into one again at 665 r as the compressor exits stall, and finally the compressor exits the stall at 674.5 r.