Evaluation of Bleed Valve Rate Requirements in Nonlinear Control of Rotating Stall on Axial Flow Compressors

Abstract

In this paper we evaluate the actuator rate requirements for control of rotating stall using a bleed valve and provide tools for predicting these requirements. Modification of both the stable and unstable parts of the compressor characteristic via addition of continuous air injection serves to reduce the requirement of a bleed valve used for the purpose of rotating stall stabilization. Analytical tools based on low order models (2-3 states) and simulation tools based on a reduced order model (37 states) are described. A bleed actuator rate limit study is presented to compare the actuator requirements predicted by theory, simulation, and experiment. The comparisons show that the predictions obtained from theory and simulations share the same trend as the experiments, with increasing accuracy as the complexity of the underlying model increases. Some insights on the design of a bleed-compressor pair are given.