Structural characteristics analysis of extra–high–head pump–turbine-unit under extreme-pressure working-conditions

Abstract

During transient processes in extra–high–head pumped–storage power plants, the prototype pump–turbine-units must be able to withstand sudden changes in water pressure within the delivery system. Extremely high or low pressures can act on structures in the short or long term and can cause damage, challenging the efficient, safe and healthy operation of prototype pump–turbine-units. So it is very important to adequately evaluate the structural robustness and stability of the extra–high–head pump–turbine prototype in the design period. In this study, the structural characteristics of an extra–high– head prototype pump–turbine-unit at extreme-pressure working- conditions were conducted. First, the full-scale CAD geometries for the prototype pump–turbine-unit were created. Next, the CAD geometries were meshed with tetrahedron elements to obtain the numerical simulation model. Then apply the extreme- pressure loads on the simulation model to evaluate the structural deformation and stress of the pump–turbine-unit prototype. From calculation results, it can be found that the stresses on some structural components are beyond the yield strength, and the high-stress locations have to be redesigned to meet the industrial requirement. Based on the calculation results, technical recommendations are given to optimize the current design. The developed evaluation method in this study can also be applied to evaluate pressured pipes, tanks, and other forms of fluid machinery.