The Influence of the Characteristics of a Centrifugal Compressor on System Stability and Distortion Response

In many future propulsion applications, the compression system size will be such that either an all centrifugal or an axial-centrifugal compressor will provide an efficiency benefit to the propulsion cycle over an all-axial compressor. The aerodynamic response of a centrifugal compressor provides an inherent stability benefit to a compression system. This work examines the influence of a centrifugal impeller on axial-centrifugal compression system stability under clean and distorted conditions. A dynamic parallel compressor model is used to simulate the behavior, and comparisons to data are performed. The effects of pressure distortion are examined, and details of the physics of the system response explained. The influence of the location of the stall trigger on the stalling and recovery behavior of the compression system is demonstrated and discussed. The work demonstrates that a simple dynamic parallel compressor model can be utilized to assist in the understanding and enhancement of compression system dynamic behavior involving centrifugal impellers.Copyright © 2012 by United Technologies, Corp.