Numerical investigations on the key contributing factor and flow features of compressor stall hysteresis

Abstract

The key contributing factor and flow features of stall hysteresis in compressor are explored in this paper. With the help of Moore-Greitzer model, the ratio of shut-off head to compressor characteristic semi-height is considered a key factor affecting the compressor stall hysteresis: the extent of the hysteresis region gradually decreases or even disappears as the ratio increases. Then, an equivalent method, reducing the ambient pressure behind the throttle valve, is applied in NASA Rotor 67 by numerical simulation to verify the impact of the ratio and explore the flow features during this process. The numerical results show that with the ambient pressure decreasing from 1.0 atm to 0.75 atm, which is equivalent to the increase of the ratio, the mass flow rate under stall condition increases, and the extent of the hysteresis region decreases significantly. The development of the stall cells is closely related to the ratio. Three large stall cells are predicted to rotate along the annulus at low ratio, while there is a large stall cell surrounded by several small stall cells at high ratio. The passage blockage is obviously weakened as the ratio increases. The ratio has a promoting or inhibiting effect on the development of the stall cells, and this further affects the stall hysteresis.