叶片转动对涡轮间隙内部流动影响的数值研究  

SIMULATION OF EFFECTS OF BLADE ROTATION ON TIP CLEARACNE FLOW IN AXIAL TURBINES

作　　者：牛茂升[1] 臧述升[1] 

机构地区：[1]上海交通大学机械与动力工程学院叶轮机械研究所,上海200240

出　　处：《力学学报》2009年第5期628-634,共7页Chinese Journal of Theoretical and Applied Mechanics

摘　　要：机匣与叶片的相对转动是影响涡轮叶顶间隙流动的重要因素之一.对LISA 1.5级轴流涡轮间隙内部流动的数值计算结果表明:叶片转动对涡轮间隙流动有阻塞作用.叶片静止时,由于阻塞作用消失,导致间隙入口速度增大,间隙流量增加,并且通过间隙的流体全部卷起形成间隙涡.同时在叶片顶部吸力面侧前缘、中部各形成一个间隙涡,使得间隙流动损失增加.而且转速下降会加剧动叶出口截面气流过偏/偏转不足现象.同时叶片静止时,间隙前部各个弦长截面内静压自间隙入口开始一直呈增加趋势,直到叶片尾缘附近截面,间隙截面内静压才逐渐稳定.Blade rotation is one of the most important factors that affect tip clearance flow in turbine rotors. This paper presents a numerical investigation of flow structures within tip clearance of the LISA 1.5-stage axial turbine. It shows that blade rotation obstructs tip clearance flow in axial turbines. When blades are stationary, relative velocity at gap entrance becomes higher due to the disappearance of blocking effect, to induce much more fluid into tip clearance. Furthermore, all the leakage flow rolls up to form tip clearance vortex. One more tip clearance vortex near the leading edge occurs beside the familiar one at the mid-chord, leading to greater flow losses. Moreover, over-under-turning induced by secondary flow increases with the decrease of blade rotation speed. Also it can be found that in forward profiles the static pressure continues to increase from the entrance to the exit of the tip clearance, and it becomes more uniform in the profile near the trailing edge.

关 键 词：间隙流动 间隙涡 叶顶分离涡 通道涡 二次流 

分 类 号：TK474.7[动力工程及工程热物理—动力机械及工程]