SLIPPING STALL

Phenomena are described of a 'slipping' blade-tip stall in an axial 100%-reaction compressor. The slipping stall is defined as a series of adjacent local stalls that arise when dP/d alpha becomes negative, where P is the lift force and alpha is the angle of attack. A gas leakage scheme in the stalling zone is considered, and formulas that describe the stall are developed. It is found that: (1) The rotating slipping stall is a self-oscillatory process whose energy is taken from the compressed gas; (2) The stall is caused by a sudden change in gas-flow conditions at the runner blades; (3) The analysis presented in the article permits evaluating, in the first approximation, the effect of runner rpm upon the speed of stalling and upon the flow-pulsation amplitude with a constant throttle resistance. (Author) Edited machine trans. of Izvestiya Vysshikh Zavedenii. Energetika (USSR), n5 p67-75 1963.