灯泡式水轮机叶片表面空化形态的试验研究  

Experimental study on cavitation characteristics of Bulb turbine blades

作　　者：李广府 卢池 LI Guangfu LU Chi(TOSHIBA Hydro Power （Hangzhou） Co., Ltd., Hangzhou 310020)

机构地区：[1]东芝水电设备(杭州)有限公司,杭州310020

出　　处：《水力发电学报》2017年第10期102-109,共8页Journal of Hydroelectric Engineering

摘　　要：为了研究叶片表面空化形态的演变过程,针对某灯泡式水轮机基于模型试验采集了特征水头下协联工况点的空化试验数据。流态观测与空化试验同步进行,观测整个运行范围内模型转轮叶片和间隙的空化形态并以绘制草图、拍照的形式记录相应的典型空化特性。对于第四种η-σ曲线可以从能量突变点开始确定对应的临界空化系数;叶片表面的空化形态呈现游移型气泡、片状气泡、云状气泡和超空化气泡四种空化形态,可根据叶片表面的空化形态预测可能产生空蚀的位置;间隙空化先于翼型空化出现,理论上分析了间隙空化产生的原因,提高转轮室和叶片外缘的加工精度、采用合理的较大的转轮间隙可以改善间隙空化。Test data of cavitation on blade surfaces were collected from a model bulb turbine running in on-cam operating conditions under characteristic working heads, with focus on generation and development of the cavitation. Gap cavitation was also observed in the model tests and all the observations for the whole operating range were recorded in photographs and sketches. This study shows that, the critical cavitation coefficient corresponds to a flow condition characterized by a sharp change in turbine efficiency for a fourth η-σ curve. And along with the decreasing cavitation number, cavitation on blade surfaces or in the gaps at runner tips was developing though four stages： travelling cavitation bubbles, sheet cavitation bubbles, cloud cavitation bubbles, and super cavitation bubbles. Locations of cavitation erosion can be predicted according to cavitation characteristics. Higher precision of the discharge ring and blade flange or a more reasonable flange clearance can suppress gap cavitation.

关 键 词：水力机械 灯泡式水轮机 空化试验 流态观测 空化形态 间隙空化 

分 类 号：TK733.5[交通运输工程—轮机工程]