Surge Recovery and Compressor Working Line Control using Compressor Exit Mach Number Measurement

Abstract

Closed-loop compressor working line controls that act preferentially to suppress surge events offer improvements in both engine performance and simplification of engine fuel systems. This paper outlines aspects of a control strategy, applied to a military turbofan engine, to support these objectives. Compressor exit Mach number feedback was used to maintain steady running lines or limit working points during transients. The control laws used for this are described and engine test results for both low-pressure and high-pressure compression systems are presented which demonstrate effective working point control together with rapid surge detection and recovery.