Centrifugal Compressor Diffuser Rotating Stall: Vaneless vs Vaned

Abstract

Diffuser rotating stall (in both cases of a vaneless or a vaned configuration) is still one of the open questions which has never been fully understood because of the complexity of the phenomenon and the experimental difficulties to get reliable measurements in such a complex environment.

Under this perspective, Computational Fluid Dynamics (CFD) is an interesting tool to "see" the flow and provide a basic understanding of the associated physics. Several published works have shown that a simplified model of the diffuser without the upstream impeller and the downstream return channel, with realistic boundary conditions entering the diffuser, can provide a qualitative analysis of the stall onset.

This research applies CFD methods to understand the onset mechanisms of rotating stall in centrifugal compressor diffusers, comparing vaneless and vaned configurations to identify design factors that influence stability and operating range.