大涵道比风扇角区失速模化设计及非轴优化

为研究非轴对称端壁造型对大涵道比风扇角区失速流动的改善作用,对某风扇进行了平面叶栅模化设计及非轴对称端壁优化。采用数值模拟方法,以风扇根部叶型为基础进行模化设计;在此基础上,采用两种不同的控制点分布方法对平面叶栅进行非轴对称端壁优化改型。研究结果表明:模化后的平面叶栅角区失速流动及叶片加载特点与风扇原型基本一致;采用自由曲面及类两面角曲面两种非轴造型对平面叶栅角区进行优化,叶栅总压损失系数分别降低了4.57%和5.38%;将流场改善效果较好的类两面角曲面造型应用于风扇原型角区,结果表明该造型使得风扇效率提高了0.441%,角区失速现象也得到了有效的抑制。深入的流场分析表明,类两面角曲面的非轴对称端壁造型,沿流向能有效推迟压气机平面叶栅通道涡向吸力面的发展,沿径向通过使涡结构上移减弱在端壁附近吸力面附面层和通道涡的相互作用;与此同时,对大涵道比风扇原型的角区失速流动也能起到较好控制效果。

Modeling Design of High Bypass Ratio Fan Corner Stall and Non-axisymmetric End-wall Optimization

To study the effect of non-axisymmetric end-wall on the high bypass ratio fan corner stall, the fan was modeled into a cascade and optimization design of profiled end-wall was carried out. Modeling design was based on the fan root profile, and two distribution methods of control points were applied to optimize the non-axisymmetric end-wall of planar cascade. As a result, the corner stall flow and blade loading characteristics are basically the same with the fan. Two kinds of profiled end-walls reduce total pressure loss coefficient by 4.57% and 5.38% respectively. The profiled end-wall similar as blended blade and end wall shape is further applied to the hub of fan. Numerical computation results indicate that efficiency increase by 0.441% and corner stall is controlled. From detailed flow field analysis, the profiled end-wall delays the development of channel vortex to suction surface and reduces the interaction between the channel vortex and suction side surface layer by adjusting vortex place. At the same time, effectiveness of controlling corner stall of high bypass ratio fan is also presented.