Control of Compression System Surge and Rotating Stall: A Laboratory-Based "Hands-On" Introduction

Certain compression system aerodynamic instabilities manifest themselves as compressor stall phenomena. The most common of these phenomena are rotating stall and surge. These phenomena correspond to relatively high-frequency and high-amplitude flow oscillation. At the very least, these oscillations result in a dramatic loss of compression system performance and operating efficiency. However, in some instances these oscillations can result in catastrophic system failure. For these reason, rotating stall and surge must be avoided at all cost in compressor operation. Hence, modeling, dynamics, and control of these phenomena are of significant interest to industry. The purpose of this paper and its accompanying video is to provide a tutorial introduction to rotating stall and surge in compression systems. Both centrifugal and axial compressors are considered. The main goal here is to provide a rather complete phenomenological description of the physical phenomena. Emphasis is placed on those aspects of the phenomena which can and must be exploited to develop dynamical models of these phenomena which are suitable for use in control system design. A secondary goal is to overview recent progress in active control of surge and rotating stall. Emphasis is placed on recent work by the authors in active control of surge and rotating stall using 1D effectors. The videotape [1] which accompanies this paper consists of several clips. These clips display the following 1) videotaped flow visualization experiments, 2) videotaped computer animations of experimental data, and 3) videotaped control hardware experiments.