Active stabilization of compressor surge

This paper describes the stabilization of compressor surge by an active method. It is known that surge follows when small disturbances grow in an unstable compression system, and that small growth can be modelled through a linear stability analysis. An active element is here introduced to counter any tendency to instability and the control law governing the active stabilizer is determined from linear theory. We follow precisely the suggestion put forward by Epstein et al. (1986) and verify that their theory conforms to practice. The theory is verified in an experiment on a compression system whose plenum volume is controlled. Suppression of the flow instability was achieved by switching on the controller and the compressor was made to operate stably on a part of its characteristic beyond the nature stall line. Furthermore the controlled compressor is much more resilient to external disturbances than is the natural case. The controller is even effective on deep surge – a feature of great interest but hardly predictable from the Epstein et al. initiative for this kind of study.