Author(s): Zhaohui Lu; Yutong Luo; Qiao Guo; Shaozheng Zhang

Linked Author(s):

Keywords: Spiral case; External concrete; Structural characteristics; Finite element analysis

Abstract: As hydropower is developing vigorously, hydraulic-turbine units have to experience higher head to balance the large power production and consumption on the grid. It requests for higher level of structural strength and stability during operation. Water-filled and pressure-retaining spiral case is commonly used in the power houses of large-scale hydropower stations, which has a good joint bearing capacity of internal water pressure. In this paper, finite element models of the water-filled and pressure-retaining spiral case with and without external concrete under preloading pressure are established, which are used to simulate the structural characteristics when the water-filling process and concrete pouring process are completed. The results show that the maximum stress and deformation of the spiral case are significantly reduced by almost 50% under the support of concrete. Both of them are located at the inner edge and are about 200.80 MPa and 0.60 mm, respectively. The reason why the maximum stress and deformation positions of the spiral case changes after the external concrete being poured is the structural characteristics of concrete, which determine its stress and deformation distribution, and then affect the restraint effect of the corresponding area on the spiral case. The concrete can share parts of the preloading pressure from the spiral case that greatly improves the joint bearing capacity and stability of the overall structure. The conclusions in this paper can also be applied to evaluate the influence of external concrete on the spiral case structural characteristics for similar spiral case structure.

DOI: https://doi.org/10.1088/1742-6596/2752/1/012034

Year: 2023