明渠横向取水旋涡影响因素数值模拟及试验研究

明渠岸边横向取水是一种常见的取水形式,在明渠主河道与横向取水口衔接处,横向取水易产生旋涡引起取水效率降低,其影响因素及机理有待进一步探明.基于水气两相VOF方法,以中国南方某横向取水工程为例,建立了三维数值模型,并对横向取水过程中引起的旋涡进行数值模拟,探究其产生机理.同时定量分析了衔接段圆弧半径、主河道及取水流速3个因素对旋涡的影响,并通过物理模型试验进行了验证.结果表明横向取水衔接段由于河道突然扩散,导致水流脱离边壁,极易形成旋涡.同时衔接段圆弧半径、主河道及取水流速均会对涡带的生、消和形状产生重要影响.当衔接段圆弧半径变大、主河道和取水流速变小时,单个旋涡半径变小,存在时间也会有所缩短,整个涡带的存在范围也有所缩小.研究进一步深化了横向取水的水力学机理,为横向取水口的优化设计提供技术支撑.

Numerical simulation and experimental study on influence factors of transverse intake vortex in open channel

Transverse water intake along the Bank of open channel is a common form of water intake. At the junction of the main channel of open channel and transverse intake, the transverse water intake is liable to generate vortices, which resulting in the reduction of water intake efficiency. The influencing factors and mechanism need to be further explored. Based on the VOF method, a 3D numerical model of a horizontal water intake project in Southern China is established. Numerical simulation of the vortex induced by the transverse water intake process is carried out to explore its mechanism. At the same time, the influence of arc radius, main channel and water intake velocity on the vortex is quantitatively analyzed, which is verified by physical model test. The results show that due to the sudden diffusion of the river, the water flow in the transverse water intake connecting section breaks away from the side wall and is easy to form vortices. At the same time, the arc radius of the connecting section, the main channel and the water intake velocity all have effects on the generation, dissipation and shape of the vortex zone. When the arc radius of the connecting section becomes larger and the velocity of the main channel and water intake becomes smaller, the radius of a single vortex becomes smaller and the existence time of the whole vortex zone will be shortened, and the existence range of the whole vortex zone will be narrowed. The study further deepens the hydraulic mechanism of the transverse water intake and provides technical support for the optimization design of the transverse water intake.