基于NURBS的扩压叶栅非对称前缘设计

前缘对扩压叶栅叶型气动性能具有重要影响,圆弧形或椭圆形前缘吸力面和压力面侧为对称形状,未针对两侧流动差异进行不同设计。为进一步提升扩压叶栅气动性能,发展了一种基于三次非均匀有理B样条(non-uniform rational B-splines,NURBS)曲线的非对称前缘设计方法,在保证曲率连续的前提下,实现吸、压力面两侧非对称的前缘构造。将设计方法应用于两圆弧形前缘叶型改型设计,数值结果表明:与原始叶型相比,总压损失系数可分别降低26.3%和23.5%,提高了整体气动性能;同时与对称曲率连续前缘相比,在51.83°进口气流角下吸力峰强度降低13.4%,前缘转捩位置推后4.6%弦长,在大进口气流角下具有更好的气动性能。 

Asymmetric leading edge design of diffusion cascade based on NURBS

Leading edge has an important influence on aerodynamic performance of diffusion cascade. No distinct designs were performed for two sides of symmetric circular and elliptical leading edge. In order to further improve the diffusion cascade aerodynamic performance, an asymmetric leading edge design method based on the 3rd-order non-uniform rational B-splines (NURBS) curve was developed, which realized the asymmetric leading edge shape while ensuring the continuous curvature. The design method was applied to two particular blades with circular leading edge. Numerical results showed that the total pressure loss coefficient could be reduced by 26.3% and 23.5%, respectively, compared with original blade profiles，and the overall aerodynamic performance was developed. At the inflow angle of 51.83°, compared with the symmetric curvature continuous leading edge blade, the leading edge suction peak intensity was reduced by 13.4%, and the leading edge transition onset was delayed by 4.6% chord length. The diffusion cascade overall aerodynamic performance was better with big inflow angle.