Abstract: Fork pipe structure is widely used in all kinds of water conservancy projects, its structural safety and hydraulic performance are the key to optimize the design, and both of them interact with each other, which will have an important impact on the comprehensive performance and operational safety of water conservancy projects. In this paper, the symmetrical fork pipe structure and hydraulic characteristics of a pumping and storage power station are optimized and designed, and the three-dimensional finite element method is used to carry out stress analysis on the initial design and optimization scheme of the fork pipe structure, and the calculation results show that the stress distribution on the waistline side of the fork pipe after optimization has been effectively improved compared with the initial design scheme. Based on the optimization of the turnpipe structure, the hydraulic model of the turnpipe with different bifurcation angles and rib width ratios is used to calculate and analyze the three-dimensional flow field under power generation and pumping conditions, and the bifurcation angles and rib width ratios of the turnpipe with better internal flow distributions and smaller head losses under all conditions are determined by orthogonal optimization strategy. It is found that the relationship between structural forces and hydraulic properties is not purely positive, and the optimal bifurcation angle of 75° and the rib width ratio of 0.30 are finally determined based on the orthogonal optimization idea to satisfy the structural safety and hydraulic performance.

Key words: structural calculation, hydraulic performance, orthogonal optimization, forked pipe