凹槽导叶式处理机匣轴向叠合量对风扇性能的影响

Numerical simulations were performed to investigate the effects of recess vaned casing treatment (RVCT) with four different blade chord exposures on a lift fan. According to the results, as the blade chord exposure extended, the stall margin of fan with RVCT increased by 1.27%, 8.01%, 12.3%, 32.4%, respectively, while the efficiency reduced by 0.82%, 1.38%, 2.2%, 4.1%, respectively, at design point. The introduction of RVCT resulted in the local circulation between recess cavity and main passage, the incidence and blade tip blockage decreased, the pressure difference between pressure and suction sides was balanced. With the increase of blade chord exposure, local circulation became much more intense and stall margin of the fan was enhanced. Also, the influence of RVCT on fan performance depended on the flow interaction between recess cavity and main flow, particularly, the bleeding and injection were primary parameters reflecting the capability of stabilizing the fan.