凹槽导叶式处理机匣轴向叠合量对风扇性能的影响

Effects of blade chord exposure of recess vaned casing treatment on fan performance

为探索凹槽导叶式处理机匣(RVCT)轴向叠合量对风扇性能的影响,选取升力风扇为对象,采用数值模拟方法对实壁机匣和4种不同轴向叠合量的凹槽导叶式处理机匣进行研究。结果表明:随着轴向叠合量的增大,带处理机匣风扇相比实壁机匣风扇裕度分别改进1.27%、8.01%、12.3%、32.4%,设计点效率分别下降了0.82%、1.38%、2.2%、4.1%;处理机匣的引入使得凹槽与主流通道间形成局部循环流动,减小了来流攻角和叶顶低能流体的堆积,平衡了叶顶吸、压力面压差,且轴向叠合量越大,局部循环越强烈,风扇稳定性提高;凹槽与风扇主流间的交互流动决定着处理机匣对风扇性能的影响,其中抽吸流和喷射流是反映处理机匣扩稳效果的两个重要参数。

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.