摘要
为研究混流式水轮机叶道涡工况下叶片表面空化现象,选取了6个典型工况开展机组全流道仿真模拟。首先分析了转轮域流线分布、不同叶高处的速度分布,表明叶道涡工况下转轮叶道内水流连续稳定的速度分布被破坏;通过叶片表面压力分布和空泡体积分布,发现叶道涡将加剧叶片压力面的压力梯度变化,导致叶片近出水边区域压力面和吸力面的压力差加大,造成叶片压力面出水边与泄水锥连接处发生空化现象;最后选取叶道内水体的体均湍动能、湍动能总量和湍动能最大值作为叶道涡密度、广度和强度特征,探究了水头和功率变化对叶道涡产生的影响,结果表明功率变化对叶道涡密度和广度方面的影响大于水头,而水头影响作用更多地体现在叶道涡强度变化上,且随着叶道涡密度、广度和强度增大,叶片表面空化面积将进一步扩大。
In order to study the cavitation phenomenon of runner blade surface of the Francis turbine in channel vortex condition, six typical working conditions were selected to simulate the whole flow passage of the turbine unit. By analyzing the streamline distribution in the runner area and the velocity distribution at different blade heights, it was found that the continuous and stable velocity distribution of the water flow in the blade passage was broken by the blade passage vortex. Though the pressure distribution and the cavity volume distribution of the blade surface, it was also found that the pressure gradient change of the blade pressure surface will be aggravated by the blade passage vortex. The pressure gradient change on the blade surface resulted in the pressure difference between the pressure surface and the suction surface of the blade near the water outlet to increase, causing cavitation phenomenon at the junction of the pressure surface of the blade and the discharge cone. Finally, the average turbulent kinetic energy, the total amount of turbulent kinetic energy and the maximum value of turbulent kinetic energy of the water in the blade channel were used as the characteristics of the blade channel vortex density, breadth and strength to explore the influence of the head and power changes on the blade channel vortices. The results show that the power change has a greater impact on the blade channel vortex density and breadth than that of water head. The impact of water head was more reflected in the change of the blade channel vortex strength. What is more, with the increase of blade channel vortex density, width and strength, the cavitation area on the blade surface will be further enlarged.
作者
岳林林
段然
何严希
刘颉
许颜贺
袁晓辉
YUE Lin-lin;DUAN Ran;HE Yan-xi;LIU Jie;XU Yan-he;YUAN Xiao-hui(School of Civil and Hydraulic Engineering,Huazhong University of Science and Technology,Wuhan 430074,China)
出处
《水电能源科学》
北大核心
2022年第5期164-168,共5页
Water Resources and Power
基金
国家重点研发计划课题资助(2021YFC3200305)
中央高校基本科研业务费专项资金资助(2019kfyXJJS137)。
关键词
混流式水轮机
转轮叶片
叶道涡
空化现象
水头
功率
Francis turbine
runner blade
channel vortex
cavitation phenomenon
water head
power
