吸力面附面层抽吸在三维高负荷扩压叶栅中的作用机制

对某矩形高负荷扩压叶栅在不同弦向位置开设全叶高抽吸槽的5组方案进行了数值研究,分析了抽吸槽弦向位置等参数对抽吸量分布规律的影响;通过叶栅实验探究了局部展向抽吸方案的效果.数值仿真的计算域包含吸附叶片内部的真空腔,边界条件按照实验条件设置.研究发现:全叶高抽吸方案的抽吸量沿展向大致呈C型分布;叶高中部和端部的主要抽吸效果都体现在叶高中部流场,端部的抽吸量对叶栅角区的回流有一定的抑制效果.抽吸量沿展向的分布规律受叶栅流道和叶片内腔流场的共同作用,因此应根据三维高负荷扩压叶栅流场的具体特性对吸力面抽吸槽/孔进行细化设计.

Mechanism of suction surface boundary layer suction in three-dimensional high loaded diffuser cascades

The highly loaded diffuser compressor cascade with a full-span suction slot was numerically simulated under five different chordwise suction positions in the first step. The influences of aerodynamic parameters such as suction position on the suction flow distribution were studied in detail. Then experiments on the effects of partly-span suction flow on the performance of a three-dimensional cascade were carried out. The simulation region includs the inner cavity of the suctior blade, and the boundary conditions in simulations are set according to the experimental conditions. The suction flow is C-type distributed along the spanwise direction in full-span suction schemes. Both of the partly-span suction schemes mainly improve the flow field around the midspan, while the suction flow around the blade roots also suppress the back flow in the corner region. Both the three-dimensional flow field of the cascade passage and inner cavity of the aspirate blade influenced the spanwise distribution of the suction flow. Therefore it is necessary to design tailored suction slots/orifices according to the characteristics of the three-dimensional high loading diffuser compressor cascades.