Linear stability analysis of rotating stall in a wide vaneless diffuser

Abstract

A two-dimensional linear stability analysis of rotating stall in a wide radial vaneless diffuser is performed to determine the onset and the characteristics of rotating stall. In addition, a dedicated experiment test rig was used to study the abilities and the limits of the theoretical model. The characteristics of rotating stall (number of modes, propagation velocity, critical angle at which the instability may appear) are calculated by this method and compared to experimental results. Besides, the growth rate of each stall mode has been calculated to determine the dominant stall mode. The ability and limits of this approach is discussed.