Characteristics of casing static pressure during compressor stall

To describe the characteristics of stall cells visually, an experimental investigation is performed with the method of casing static pressure countour analysis to study the flow field at the rotor tip for a single-stage axial compressor. The results indicate that the method could observe the developing process and influence area of the stall cells visually, estimate the number precisely and the rotating speed approximately. The frequency analysis validates the veracity of the method. This method finds that there is one cell which holds 4/5 of the passage of the compressor when a stall occurs, and then the stall cell splits to two and rotates faster by opening the valve.