Abstract
In order to balance the intermittent supply of energy to the power grid, pumped storage units have to operate more and more in extended operating conditions and switch their mode frequently. During operation, the turbine unit has to withstand various axial forces that may cause deformation and fatigue damage to the key components of the machine. The excessive load could surpass the weight of the runner body, which is dangerous for the power plant. For the safe and stable operation, the simulation of the axial force under pump condition is performed by the computational fluid dynamics method (CFD) in this paper. The CFD simulation result has revealed the variation rule of the axial force with the operating condition. Besides, the conditions with pressure-balance pipelines (PBP) blockage are also investigated and the mechanism of PBP on reducing the axial force applied on the bracket has been revealed. The maximum stresses are calculated by means of Finite Element Method (FEM) and compared with the normal conditions. The result shows that the blocked PBP will increase 62.20% of the maximum stress on the support bracket.