泄洪洞内具有阻塞与扩散段的水平旋流消能方式水力特性的试验与数值模拟(2)  

Model tests and numerical simulations on hydraulic characteristics of level rotary flow in spillway tunnel with blocking and diffuser(II)

作　　者：葛晨[1] 牛争鸣[2] 李奇龙[2] 蔺娜[3] 

机构地区：[1]中国电力工程顾问集团西北电力设计院,西安710075 [2]西安理工大学,西安710048 [3]中国水电工程顾问集团西北勘测设计研究院,西安710065

出　　处：《水力发电学报》2015年第1期73-78,92,共7页Journal of Hydroelectric Engineering

摘　　要：本文采用Realizable k-ε双方程紊流模型和VOF法,并结合模型试验,对水平旋流复合式内消能泄洪洞的流速分布、旋流角、湍动能、耗散率、以及消能率进行了分析和计算。结果表明:起旋室段存在径向速度,切向入流条件较差;轴向流速沿径向呈对称分布,最大值靠近洞壁;切向流速沿径向呈反对称分布,最大值靠近气水交界面,可视为组合涡分布;旋流角在起旋室段与阻塞扩散段变化较大,中间旋流洞段变化较平缓;紊动能、耗散率在起旋室出口附近及阻塞扩散段较大;计算总消能率约为83%,其中竖井段、旋流洞段和阻塞扩散段各占4.58%、28.45%和49.51%。旋流阻塞的设置不仅减小了旋流洞内发生空化空蚀的可能性,而且增大了洞内消能率,提高了适用水头。According to both the model tests and numerical simulations with realizable κ-ε turbulence model and VOF model, analysis and calculations of the spiral flow in a compound internal energy dissipation spillway tunnel are presented, focusing on velocity distribution, rotational flow angle, turbulence kinetic energy, turbulence dissipation rate, and energy dissipation rate. The results show that radial flow velocity occurs in the vortex generator as a result of unfavorable tangential flow at the generator inlet. Over radial direction, the axial velocity is distributed symmetric with its peak close to the tunnel wall, while the tangential component is anti-symmetric with its peak close to the core water-air interface suggesting a combined eddy. Rotational flow angle in the vortex generator and blocking-expansion device changes more rapidly along the tunnel than that in the spiral-flow tunnel at middle section. Turbulence kinetic energy and turbulence dissipation rate are greater in the vortex generator and blocking-expansion device. The calculated total energy dissipation rate of about 83% is split into 5% in shaft section, 28% in swirl-flow section, and 50% in blocking-expansion device. The blocking device can not merely reduce cavitation potential, but increase energy dissioation rate.

关 键 词：水力学 复合式内消能泄洪洞 数值模拟 流速分布 旋流角:湍动能 

分 类 号：TV651.3[水利工程—水利水电工程]