大型泄洪洞有压弯道水力特性

Flow characteristics in a circular-section bend of high head spillway tunnel

为系统研究泄洪洞有压弯道的水力特性,结合大比尺物理模型,采用三维Reynolds应力数学模型(RSM)对不同来流流速、弯曲半径和转角的有压弯道进行了计算,用模型试验资料对弯道的压力和流速分布进行了验证,计算值和试验值吻合良好。给出了弯道的内外压差和最低压力的规律、二次环流的发生和发展过程,弯道的水力特性和弯曲半径关系较大,并提出了一些工程措施。

Large-scale physical model experiments （1：38） combined with three-dimensional （3D） Reynolds stress question model（RSM） numerical modeling are used in this study to explore the hydraulic characteristics in a cireular-section bend of high-head spillway tunnel. The 3D RSM is used to simulate the incoming velocities under different pre-designed bend radius and angle conditions, as well as the pressure and velocity distributions in the bend. The simulations compare well with the ex- perimental data. Both occurrence and development of the secondary circulation in the bend are successfully simulated by RSM. An expression for optimizing the minimum bend pressure is derived. The expression establishes the relation between the bend pressure and velocity, and the pre-designed bend radius and angle conditions. The result of using the expression shows that the bend radius is the premier parameter to be considered when designing a circular-section bend of high-head spillway tunnel.