水轮机转轮空蚀量预估的一种近似算法

An approximate calculation method for estimating turbine runner cavitation pitting

水轮机空蚀一般在原型机上采用直接测量的方法进行。目前还没有一个很好的方法对空蚀情况进行定量预估,本文根据国外水泵空蚀的经验公式,提出一种通过观测水轮机模型试验中各工况下转轮空化区域长度,采用经验公式预估原型水轮机转轮空蚀程度的方法。作者详细介绍了公式各参数意义并结合国内某电站模型试验空化观测情况进行实例计算,预测空蚀最大深度、面积及金属失重,计算结果表明采用该方法具有一定精度。论文最后对公式的适用范围进行了探讨。

Turbine cavitation pitting quantity was usually calculated by direct turbine operation. So far, no perfect method can be referred to evaluate the measurement on prototype degree of cavitation pitting quantitatively. Based on an overseas experimental formula for water pump cavitation pitting, the authors put forward a new method to make estimation of turbine cavitation pitting quantity. According to the observed runner cavitation lengths under different working state in model tests, estimation can be made by using the experimental formula to predict the degree of prototype turbine cavitation pitting. The meanings of each parameter in the formula are introduced in detail. An illustration of the new method applied for a domestic power plant is given. The observation data in the model test of the plant are used to calculate the maximal depth, area and metal weight losses of cavitation pitting. The result indicates that the new method is precise to a certain extent. The applicability of the formula is also discussed.