微型低比转速混流式水轮机的 水力特性分析

本文介绍了一种由冷却塔中冷却循环水驱动的微型水轮机。该机流量限于循环水流量、功率限于风机功率、水头依赖流量与功率；其蜗壳平面尺寸小，不设导水机构，转轮流道狭长。为了解该水轮机的水力特性，采用数值模拟与试验相结合的方法对其进行研究。研究表明：对于同一水轮机，其内流场特性表现出相似性，能量和压力脉动等水力特性也表现出相似性，水力效率相等，水力损失相等。该水轮机的水力效率较低，水力损失较大，其水能主要损失于引水部件，其次是转轮；由于引水部件距离转轮近，其固定导叶叶道的水力振动幅度达到10%以上。

Analysis on hydraulic characteristics of micro Francis hydro-turbine with low specific speed

A micro Francis hydro-turbine driven by the circulating cooling water in cooling tower is introduced herein; of which the flow rate is restricted to the circulating water discharge，the output power is confined to that of the cooling tower fan and the head is relied on both the discharge and the output power.It has a small dimension with a long and narrow flow path of the runner and without water guiding mechanism.In order to know the hydraulic characteristics of it，a study is made with the method of numerical simulation combined with the relevant experiment.The study result shows that similarities are presented by the characteristics of the flow field inside of it，while the hydraulic characteristics of energy，pressure fluctuation，etc.also show similarities with the same hydraulic efficiency and loss.The hydraulic efficiency of the turbine is lower with a larger hydraulic loss; of which the hydro-energy is lost mainly from the water diversion parts and secondly from the runner.Furthermore，the amplitude of the hydraulic vibration on the blade channel of stay vane is higher over 10% due to a less space between both the diversion parts and the runner.