摘要
本文对轴流转桨式水轮机轮缘间隙流动进行试验研究,详细研究了不同工况下轴流转桨式水轮机轮缘间隙流动的空蚀形态。受桨叶角度和开度的影响,轮缘间隙流动有五种的空蚀形态,这几种空蚀形态随开度的变化,可能有一种或两种同时出现。其中侵蚀危害性最严重有Ⅰ、Ⅱ和Ⅴ三种空蚀形态。在负的桨叶角度,协联工况的左边运行时,在叶片的背面轮缘处产生第Ⅰ中泄漏涡带,同时在叶片进口正面头部轮缘处产生泄漏流动和二次流动漩涡相互作用所引起的小面积的强烈空蚀空泡为第Ⅱ种,它是叶片头部缺角的主要原因;在正的大桨叶角度、大开度情况下,间隙泄漏流动主要发生在叶片的背面轮缘处尾部第Ⅴ种空蚀形态,泄漏涡带与主流相互作用形成一个长长的涡带扫射下部转轮室,是叶片背面尾部和转轮室空蚀破坏的主要原因。
The experimental investigation of the tip clearance cavitations on blades flange of Kaplan turbine is presented in this paper. Five types of cavitations in the tip clearance flow on blades flange have been developed at the different run blade angle and guide vane angle. Serious damages are occurred with the types of Ⅰ 、 Ⅱ and Ⅴ. At the negative run blade angle, the tyes of Ⅰ and Ⅱ are observed, type Ⅰ of cavitating vortices from the sheet cavitations along the flange suction side covers the blade flange completely, tip leading edge and the type of Ⅱ occur with large guide vane angle, there are tip vortex cavitations, tip clearance cavitations and second flow vortex at the blade leading edge. Vortex region of tip near the flange at the rear part of blades is observed named Ⅴ type, the sheet cavitations looks very foamy and is formed by cavitations streaks that grow during their transport with the main flow and tail vortex, if forms a sheet cavity further downstream. This is the reasons of eroding trailing edge at the rear part of blades and hub.
出处
《水力发电学报》
EI
CSCD
北大核心
2005年第4期67-72,共6页
Journal of Hydroelectric Engineering
基金
国家自然科学基金资助项目(50379044)
关键词
轴流转桨式水轮机
轮缘间隙空蚀
试验研究
不同工况
Kaplan turbine
tip clearance cavitations on blade flange
experimental investigation
different operating conditions
