The Study Of Hydraulic Pressure Fuctuation In HL160on The Basis Of Numerical Simulation

Hydropower turbine group is the core component of hydropower station, and it isvery important to integrity of hydropower station. With the increasing of unit capacityand installation size,the improving of specific speed,turbine vibration problem hasbecome increasingly prominent.So stability of francis turbine becomes very important.Flow field unsteady flow phenomena is one of the main causes of vibration. Theinternal mechanism of the hydraulic vibration aspects can be studied by the analysisof three-dimensional unsteady flow and unsteady in Francis turbine using CFDtechnology.It has a very important practical significance to the improvement of turbineintegrated hydraulic performance and the improvement of Hydroelectric generating setrunning stability.In this paper, study object is school test bench HL160-LJ-25model turbine, Themain contents are as follows:（1）Solid modeling and meshing of overcurrent runners of volute vanes and drafttube was built by the using of3D modeling software solidworks and meshing softwareICEM. Solid modeling and structured grid of overcurrent runners of guide vanes andrunner was built by using of professional rotating machinery software Bladegen andTurbogrid.（2）Because the shape of the volute and vanes together, so there is three pairs ofinterface. Handling interface is not moving vanes and guide vanes using GeneralConnection, while using the Frozen Rotor Model connection between the rotating wheeland guide vane and draft tube. Three-dimensional unsteady turbulent was conducted inthe turbine overall flow passage in different conditions by using of k-ε turbulence mode.The study found overall flow characteristics under high flow conditions worse thanoptimal conditions, but better than the low flow conditions in runner.（3）Three-dimensional unsteady turbulent,which unsteady three-dimensionalcalculation results as initial conditions in#1small flow conditions was conducted inturbine. The flow characteristics of viscous flow field between the guide vanes andrunner and the flow field in the draft tube was analysis.Study found that fixed positionmonitoring point is always pressure maximum and minimum pressure because of theimpact of guide vanes flow. At different time steps, the pressure of fixing monitoring points pressure is constantly changing with the rotation of the wheel. Vortex developedfrom runner exports to the elbow section, and passed the low pressure area of eachsection. Greater pressure pulsation occurred in straight cone section. Pulsating focusedon the outer wall side of the elbow, and pressure pulsation wassmall in the lower sectionof the elbow until the diffuser. Analysis results show that, although there are also flowinstability in runner, not ideal phenomenon of the pressure distribution, but the pressurepulsation amplitude is very small and no obvious rule.Further research needs to be done.