阻塞型竖井旋流泄洪洞水力特性研究  

Study on Hydraulic Characteristics of a Vortex Drop Shaft Spillway with a Blocker

作　　者：阳洲 尹进步[1] 魏柯榜 徐根海[1] 闫秀秀 卢洋亮 YANG Zhou;YIN Jinbu;WEI Kebang;XU Genhai;YAN Xiuxiu;LU Yangliang(College of Water Resources and Architectural Engineering,Northwest Agricultural and Forestry University,Yangling 712100,China)

机构地区：[1]西北农林科技大学水利与建筑工程学院,陕西杨凌712100

出　　处：《应用基础与工程科学学报》2023年第4期828-842,共15页Journal of Basic Science and Engineering

基　　金：国家自然科学基金项目(51279170)。

摘　　要：为了解决竖井旋流泄洪洞下部出现高速低压而导致的空化空蚀风险,提出在竖井中部设置垂直阻塞的布置形式.主要通过数值模拟的方法,对设置不同收缩度的阻塞竖井旋流泄洪洞的流态、压强、三维流速、空化与消能特性等进行了系统研究.研究结果表明:收缩度不宜过大或过小,过大则泄流能力不足,过小则流场变化不明显.一定收缩度的阻塞有利于减小空径比,增大旋流角,进而增大壁面压强,同时阻塞的存在使得上部旋流合流速与轴向流速减小,这一增压减速效果显著增大了空化数,大大降低发生空化空蚀的风险.另一方面阻塞的设置有效降低了井底水跃与水垫的紊动程度,底板压强值降低,且压强分布更加均匀.虽井底区域消能率有所下降,但旋流区消能率的大幅增加能与之弥补.研究成果充分揭示了阻塞竖井旋流泄洪洞的流场特征,可为其进一步研究应用提供参考.The vortex drop shaft spillway with a blocker installed in the middle of the shaft was proposed to reduce the risk of cavitation,which caused by high flow velocity and low pressure.Hydraulic characteristics such as the flow pattern,pressure,three-dimensional velocity,cavitation number and energy dissipation of the spillway equipped with different blocker are mainly obtained and systematically studied by numerical simulation.The results shows that the degree of shrinkage should be selected reasonably to avoid insufficient discharge capacity or insignificant variation in the flow field;The suitable shrinkage degree is able to reduce the ratio of air-core radius to cross-sectional radius and increases the swirl angle,leading to an increase in wall pressure.The resultant velocity and axial velocity of the upper swirling flow decreases along the shaft wall.The reduced probability of cavitation is attributed to the fact that the contracted structure with pressurization and deceleration effect greatly improve the cavitation number.The setting of blocker effectively reduces the turbulence of the water jump and the water cushion at the bottom of the well,in which the pressure is reduced and evenly distributed.Although the energy dissipation rate in energy dissipation well decreases,the substantial increase in the energy dissipation rate of the swirling flow can make up for the loss.The research results fully reveal the flow field characteristics of the vortex drop shaft spillway with a blocker,which can provide a comprehensive insights for the future research and application.

关 键 词：阻塞竖井旋流 数值模拟 压强 增压特性 流速 空化 消能率 

分 类 号：TV135.2[水利工程—水力学及河流动力学]