摘要
以三峡右岸地下电站为例 ,对含变顶高尾水系统的地下电站的过渡过程进行了理论分析与计算 ,结果表明 :蜗壳最大动水压力与尾水系统的布置方式关系不大 ,主要取决于机组上游侧水流惯性的加速时间、水轮机工作特性和导叶关闭时间及关闭规律 ;从机组甩负荷的转速变化动态过程可看出 ,机组转速最大升高发生在导叶关闭过程之中 ,最大转速上升率的大小主要取决于导叶关闭时间的长短和水轮机引用流量的大小 ,关闭时间越长 ,流量越大 ,机组转速升高值越大 ;尾水管进口真空度除与下游尾水流道的水流惯性时间、水轮机工作特性、导叶关闭规律等因素有关外 ,与下游水位的关系也很密切 ;当下游水位最低时 ,尾水管进口真空变化最明显 ,随着下游水位的上升 ,尾水管进口真空度逐渐改善。为今后同类电站的设计与计算工作提供了一定的借鉴与参考。
Taking TGP underground powerstation on right bank as an example,theoretical analysis and computation are conducted on transitional state of flow in tailrace system with varying crown elevation,and the analysis results demonstrate that the maximum dynamic water pressure on spiral case has no close relation with layout of tailrace system,but mainly depends on upstream flow accelerating time of power units,operating characteristics of hydraulic turbines and closing time and regulation of guide blades.From dynamic variation process of rotational speed in load rejection,it can be seen that the maximum step up of rotational speed takes place in the closing process of guide blades and the max. step up rate depends mainly on closing duration of guide blades and the amount of turbine discharge.For longer closing time and larger discharge,the step up of rotational speed is larger.Besides the flow inertia time of downstream tailrace flow passage,operation behaviour of turbine,closing regulation of guide blade,the vacuum degree at tailrace adit has also close relation with downstream water level.The vacuum degree at tailrace adit varies most significantly at the lowest downstream water level and improves gradually along with the rising of downstream water level.This analysis and computation can be referred for the design and computation of similar powerstation.
出处
《人民长江》
北大核心
2002年第7期1-3,共3页
Yangtze River
关键词
地下电站
变顶高尾水系统
计算理论
三峡水利枢纽
明渠
underground power station
tailrace system with varying crown elevation
computation theory
transitional process
TGP
