灯泡贯流式水轮机增减负荷动态特性分析  

Numerical analysis of the dynamic characteristics of the bulb turbine during decreased and increased load transition processes

作　　者：赵亚萍[1] 赵晨 秦笛舸 郑小波[1] 郭鹏程[1] ZHAO Yaping;ZHAO Chen;QIN Dige;ZHENG Xiaobo;GUO Pengcheng(School of Water Resources and Hydroelectric Engineering,Xi’an University of Technology,Xi’an,710048,China;XD Smart Energy Technology Co.,Ltd.,Xi’an,710075,China)

机构地区：[1]西安理工大学水利水电学院,西安710048 [2]西电智慧能源科技有限责任公司,西安710075

出　　处：《农业工程学报》2024年第5期99-108,F0003,共11页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(52009105;51839010);陕西高校青年创新团队(2020-29)。

摘　　要：水轮机频繁经历变负荷工况转换过程,使得机组在较短时间内工作参数急剧变化,严重影响电站稳定运行。该研究以某贯流式水轮机为研究对象,在考虑自由液面和水体重力的情况下,采用动网格技术对贯流式水轮机相同出力范围下的减、增负荷过渡过程的动态特性进行分析。研究结果表明:由于增负荷和减负荷过渡过程的起始工况导致起始流动状态不同,因此在相同出力时,机组内的流动分布不同,减负荷过程尾水管内的涡流面积及强度明显小于增负荷工况,且尾水管涡带尺度也明显小于增负荷过程;相比于增负荷过程,减负荷过程中转轮叶片大范围的低压区极易引发空化;机组内的水压力脉动主要以尾水管涡带引起的0.1f_n(f_n为转频)低频压力脉动和转轮的旋转引起3f_n的高频压力脉动为主,增负荷过程的压力脉动幅值明显大于减负荷过程,两种压力脉动共同作用,使得贯流式水轮机主要振动区域集中于转轮。研究结果对贯流式水轮机的设计与运行具有一定的指导意义。Hydraulic stations often undertake the tasks of peak and frequency regulation of the power grid,due to the excellent performance and relatively low costs.Thus,operation conditions vary frequently in the turbine.These rapid changes in operating parameters within a short time can seriously affect the stable operation of the power station.In this study,the dynamic characteristics test of a prototype tubular turbine was implemented by the dynamic grid technology,in order to consider the gravity of free surface and water gravity during the transient process of load decrease and load increase under the same output range.The research results showed that:The flow distribution in the unit was different at the same output.The reason was that the different initial flow states were caused by the initial operating conditions in the transient process of load increase and decrease.In the process of load decrease,the center area of the draft tube inlet was affected by the water discharge cone.A low-velocity zone of the same diameter occurred as the water discharge cone.The area of this low-velocity zone was further expanded as the main flow flows downstream into the diffusion section of the draft tube.There were outstanding vortexes and refluxes at the outlet of the draft tube.The starting condition of the load increase process was a partial load condition with a low flow state.The flow state in the unit was more turbulent in the whole load increase process,compared with the load decrease process.The low-velocity areas in the tailpipe in the load increase process were outstandingly larger than those in the load decrease process for the same output.The vortex begins at the inlet area of the tailpipe and spreads into most of the entire tailpipe area.This vortex state in the draft tube posed a great impact on the stability of the turbine.The vortex area and intensity in the draft tube during the load decrease process were significantly smaller than those during the load increase process.Even there was no exception at the vortex sca

关 键 词：数值模拟 振动 压力脉动 增减负荷过渡过程 涡带 水轮机 

分 类 号：TK7333[交通运输工程—轮机工程] S225[动力工程及工程热物理—流体机械及工程]