带根部间隙的直、弯压气机静叶流场的实验

Experimental investigation of flow field in both straight and positive bowed stator passages with cantilever blades

关键词:  压气机  正弯静叶+  旋涡结构+  实验研究

Key words:  Compressor  Positive bowed stator+  Vortex structure+  Experimental investigation

摘要:

为了获得正弯静叶在动态压气机中的性能特点,分别对采用带根部间隙的直静叶和正弯静叶的重复级低速轴流压气机在不同流量工况下的静叶出口流场进行了实验测量,结果表明,正弯静叶对气流的扩压能力在设计工况和近喘工况下强于直静叶,在最大流量工况下弱于后者。设计工况下,流道内存在的两个主要旋涡结构,分别为上通道涡和刮削涡,且刮削涡在正弯静叶流道内的尺度要远小于直静叶流道中;最大流量工况下直静叶流道中的刮削涡明显增大而正弯静叶中则基本保持不变;近喘工况下分离严重,旋涡随之消失。考查出口气流角可以发现,正弯静叶对气流的折转能力在整个流量工况下都弱于直静叶,但沿叶高的分布更为均匀。

Abstract:

Experimental investigation was performed in a double stages low speed axial compressor.The traverse flow field at the exit of second stator was measured in details at different working condition for both straight and positive bowed stator passages.The results show that the pressure diffusion ability in positive bowed stator passage is stronger than in straight stator at design condition and near stall condition but weaker in near maximum flow condition.There are two main vortexes in stator passage at design condition,which are up passage vortex and scraping vortex,respectively.The scraping vortex in straight stator passage distributes a large area but much smaller in positive bowed stator passage.The up passage vortex disappears in near chocking condition.However,the scraping vortex enhances in the straight stator passage while it changes a little in positive bowed stator passage.In near stall condition,the flow separation happens along the full span wise and all the vortexes disappear.Compared with the outflow angle,the ability of flow under-turning in positive bowed stator passage is weaker than in straight stator in whole mass flow work condition.However,the distribution of flow angle along the blade height is more uniform in positive bowed stator passage than in straight stator passage.