Rotating Stall in Multistage Axial Compressors : 1st Report, Small Disturbance Theory 1

Abstract

A theoretical method of calculating the propagating speed of the stall cells and the condition of the onset of the rotating stall in multistage axial compressors is given. Two fundamental limitations are, firstly, that the pitch (but not necessarily the chord) of each blade row must be small compared with the wave length of the stall cell (so called actuator disc theory), and secondly, that the disturbance must be small enough to allow the linearizing assumptions. The main conclusions are as follows : (1) In multistage compressors, the propagating speed is much influenced by the distance between the blade rows, the chord length of blades, and the time lag of the boundary layer. (2) The condition of the onset of rotating stall in multistage compressors is also given. The axial distance between blade rows and the time lag of the boundary layer have some influence while the chord length has not.