Control of Rotating Stall in Axial Compressors Using Plasma Actuators

This paper proposes the use of SDBD plasma actuators to suppress rotating stall inception and extend the stable operating range of axial compressors. Plasma actuators may provide a practical low-power alternative to effectively increase the surge margin of aircraft engines with minimal or even positive impact on compressor performance. A computational study is carried out on a representative subsonic modern compressor rotor geometry to evaluate the proposed casing plasma actuation for suppression of short (spike) as well as long (modal) length-scale rotating stall inception based on their respective flow physics. The objective is to assess the optimum actuator location and required actuation strength to achieve the desired effects at low and medium subsonic compressor speed. Results show that plasma actuation near the rotor leading edge and concentrated in the tip clearance gap region most effectively suppresses both of the criteria for spike stall inception and delays the predicted stall point to a lower flow coefficient with relatively low power input. In addition, the observed increase in rotor pressure rise characteristic from the proposed actuation means that the concept, with a new suggested actuator modification, can also be used to suppress modal stall inception. The simulations indicate that actuation effectiveness decreases with increasing compressor speed and that stronger actuation strength than that of conventional SDBD plasma actuators may be needed. Some implications for the practical implementation of this concept on real compressors are also discussed.