Rotating stall inception is achieved using full-span distributed jet actuation.
The nonideal injection reduces the stall range’s extension by about the same proportion of the effective pressure increase [56].
Bleed valve
Active
Maintain the average flow through the compressor above the critical flow. The air bleeds from the plenum, so as to increase the flow through the compressor.
Recirculation alters the compressor operating point. Only use the recirculation or ambient bleeding when stall is imminent [57, 58].
Stabilisation rings
Passive
Changes the fluid dynamics; provides the stalled flow with a route back into the impeller.
A series of circumferential vanes correct the swirl flow in the axial direction; the stall cells centrifuge spontaneously into the air separator inlet and separate from the main flow.
Air separators are able to effectively suppress the stall zone after the stall cells appear [63].
