涡轮叶栅通道中的流动显示

在大尺寸低速叶栅传热风洞中对一种高压涡轮导向叶栅的流场进行了流动显示实验研究。分别采用线簇和小球浮动法对五个雷诺数下的叶栅端壁区三维流场、叶片表面和端壁表面的流动进行了显示。实验结果表明 :涡轮叶栅中有强烈的二次流动 ,并存在复杂的涡系 ;三维流动区约占叶栅通道的 40 % ;雷诺数的增大将增强端壁区的三维流动。流场显示图片说明 :叶片吸力面靠近端壁有角涡形成与发展 ,并存在一个三角形区域 ;流场显示的通道涡大小与流场测量结果吻合。本文的实验结果可用于分析端壁表面和叶片表面换热特性的形成机理

Flow Visulization of Turbine Cascade

The flow field visualization of a straight HP trubine cascade is conducted in a large scale low speed open loop cascade heat transfer wind tunnel. The 3D flow fields near the endwall of the cascade, the flows over blade surfaces and endwall surface are visualized by using cotton thread and floating small ball. The experimental results show that there are strong secondary flow and a complex series of vortices in turbine cascade. The 3D flow region occupies 40% flow passage of turbine cascade. The increasing of Re number will strengthen 3D flow near endwall. The photos of flow visualization show that corner vortex generates and develops near the suction surface of blade/endwall junction, which forms a triangle region. The size of visualized passage vortex agrees well with measurement result. The results of this paper are useful to analyse and explain the heat transfer characteristics of the endwall and blade surfaces.