Flow Characteristics and Life Analysis of Francis Turbine
The flow of Francis turbine is an unstable transient process,and the hydraulic impulse pressure pulsation during startup and shutdown will have adverse effects on the turbine components.In order to obtain the internal flow field of the turbine and the material flow field changes and pressure load information of the key parts,Tankeng Hydropower Station was taken as research object.The Creo 3D modeling software was used to build three-dimensional numerical sim-ulation model of the whole flow channel of the turbine.The Meshing was adopted to build the fluid grid model of hydrau-lic turbine.Fluent was used to carry out the flow field analysis and life evaluation of Francis turbine at different speed.The results show that the negative pressure is particularly obvious in the area close to the draft tube area due to the rota-ting effect of the turbine.With the increase of rotational rate,the negative pressure becomes more obviously.With the increase of turbine speed,the flow velocity at the edge of the draft tube pipe is higher,and the flow velocity at the outlet of the draft tube is unevenly distributed,which is more likely to produce greater resistance.The cavitation under the run-ner is gradually intense,which is caused by the gradual increase of negative pressure area behind the runner.The cavitati-on area is evenly distributed on the back of the blade near the rotor shaft,and the pressure on the pressure surface and suction surface decreases gradually.The negative pressure range of the back of the runner blade is close to 20%,resulting in cavitation damage.The stress on the runner is increasing,the stress is mainly concentrated in the tip of the blade,the increase of the maximum stress reduces the life of the runner and more likely to produce cracks.The research results can provide reference for the actual operation.
Francis turbinebladepressurecavitation characteristicsnumerical simulationlife evaluation
万方数据
维普
