试验水头和空化系数对混流式水轮机尾水管压力脉动影响的试验研究  

Experimental Study of the Influence of Thoma Number and Model Test Head on Francis Turbine Draft Tube Pressure Fluctuation

作　　者：徐用良[1,2,3] 覃大清 孟晓超[4] XU Yongliang;QIN Daqing;MENG Xiaochao(State Key Laboratory of Hydro-power Equipment(HILEM),Harbin 150040,China;China Electrical Equipment Industry Association,Beijing 100070,China;Harbin Electric Machinery Company Limited,Harbin 150040,China;China Institute of Water Resources and Hydropower Research,Beijing 100038,China)

机构地区：[1]水力发电设备国家重点实验室(哈尔滨大电机研究所),哈尔滨150040 [2]中国电器工业协会,北京100070 [3]哈尔滨电机厂有限责任公司,哈尔滨150040 [4]中国水利水电科学研究院,北京100038

出　　处：《大电机技术》2019年第1期57-63,共7页Large Electric Machine and Hydraulic Turbine

基　　金：科技部国家重点研发计划项目"国家质量基础的共性技术研究与应用-电力装备和工程建筑领域国际标准研究"(编号:2016YFF0202805)

摘　　要：本文通过试验方法研究了模型试验水头和空化系数对混流式水轮机为尾水管压力脉动的影响。首先在混流式水轮机6个典型运行工况,即空载、低部分负荷(叶道涡)、部分负荷、最优工况、额定工况和超负荷工况进行变水头和变空化系数试验。试验结果表明在试验范围内,水头对混流式水轮机尾水管压力脉动幅值影响较小;而在一定范围内,空化系数对混流式水轮机尾水管压力脉动有较大影响。通过对部分负荷和超负荷工况幅值和频率分析发现,空化系数不仅对混流式水轮机尾水管压力脉动幅值有较大影响,对其频率分布也有较大影响。最后比较了以转轮中心线为空化基准面的压力脉动试验结果和以锥管中心线为空化基准面的压力脉动试验结果。研究表明,以转轮中心线为空化基准面进行压力脉动试验比较合理,故进行混流式水轮机压力脉动相似性研究时,需考虑空化系数的差异和空化基准面的选择。In this paper, the influence of Thoma number as well as model test head on Francis turbine pressure fluctuation was investigated by experimental method. Firstly, by varying model test head and the Thoma number at 6 typical operating conditions including no load, deep part load(inter-blade vortices), part load optimum condition, rated and full load condition, investigation of the influence of model test head on draft tube pressure fluctuation was carried out. From the model test results, test head had little influence on Francis turbine draft tube pressure fluctuation amplitude as well as the frequency distribution if the Thoma number kept the same in the test range. Then,analysis is made on the influence of Thoma number on draft tube pressure fluctuation amplitude as well as frequency at the part load and over load condition. It is found that the sigma not only had an impact on draft tube pressure fluctuation amplitude but also on the frequency components distribution. Finally comparison of pressure fluctuation results were analyzed which was based on two different cavitation level for pressure fluctuation test. For France turbine pressure fluctuation test,it is reasonable of selection of runner centerline as cavitation reference level. So when study of pressure fluctuation similarity, the influence of the difference of Thoma number and selection of cavitation level should be considered.

关 键 词：混流式水轮机 压力脉动 空化系数 空化基准面 频率分布 

分 类 号：TK733.1[交通运输工程—轮机工程]