叶型对扩压叶栅角区分离的影响

Effects of Blade Profile on Corner Separation in

关键词:  扩压叶栅  角区分离  分离形式  逆压梯度  型线曲率

Key words:  Compressor cascade  Corner separation  Separation form  Adverse pressure gradient  Curvature

摘要:

为了在叶型设计阶段尽可能减小角区分离的可能性，用数值模拟方法研究角区分离形式对扩压叶栅气动性能的影响，以及叶型参数对角区分离形式和分离范围的影响。角区分离改变了吸力面的静压分布，静压沿叶展方向呈现出“C”型压力分布，与开式分离相比闭式分离加剧了吸力面的“C”型压力分布，闭式分离造成下端壁吸力面最低压力点后的流向逆压力梯度增加。分离降低叶栅扩压能力，增大损失，与开式分离相比闭式分离的气动性能降低更显著。研究结果表明:角区分离受叶型参数的影响较大，随着叶型相对厚度的增加、中弧线挠度增大、最大厚度位置后移吸力面最大厚度位置之后的型线曲率的变化梯度增大，吸力面最低压力点之后的流向逆压力梯度和吸力面展向压力梯度增大，进而增大角区分离范围，改变分离形式，由开式分离向闭式分离转变。

Abstract:

Effects of suction surface corner separation on the aerodynamic performance and effects of the blade parameters on suction surface corner separation in linear compressor cascade were researched to prevent corner separation when designing profile. Static pressure on suction surface was changed，and a C-Shape pressure distribution along span wise was built owing to corner separation. The C-Shape pressure distribution of closed separation is much more significant than that of open separation. Stream wise adverse pressure gradient after the lowest pressure point on suction surface of closed separation is larger than that of open separation. Diffusion capability decreases and loss increases because of the separation，aerodynamic performance degradation of closed separation is larger than that of open separation. Results show that corner separation is influenced by profile parameters significantly，with the increase of the blade thickness，the maximum thickness position moving afterwards and the deflection of mean camber line，the curvature gradient after the max blade thickness position of suction surface increases，the stream wise adverse pressure gradient on the suction surface after the lowest pressure point increases，the scale of separation zone increases，even the separation form could change from open separation to closed separation.