Research Of The Francis Turbine Channel Vortex On Higher Rated Head

Chanel vortex is a phenomenon of swirl flow caused by the water off the flow in runnerblades imported near the crown and develop between the runner blade when Francis turbinerun at the deviation from the optimal condition. That influence the stability of the turbine andcause the hydraulic vibration.When the vibration exceeds the allowable value, especially inthe vibration state for a long time, even component resonate with the turbine, it will seriouslythreatens the safety operation of hydropower electromechanical equipment and staff’spersonal safety.Vane is an important flow component of Francis turbine, for playing a shutdown turbinerunning, changing the role of the discharge flow of turbine to meet the requirements of theinflow Angle of the runner import. The position and airfoil of the turbine guide vane areimportant to the internal flow field in turbine,because it can change the flow regime.This paper is for the channel vortex by a hydraulic vibration Francis turbine in thesouthwest which the vortex happen in the situation of higher than the rated head and under therated load. Through the theory of the velocity triangle, the reasons of vibration occurring isfound and the method to reduce vibration by changing the position and the shape of guidevane in order to achieve the water flow regime of the runner import. It will be providedthrough the use of the calculating software ANSYS CFX and compare with the real date toachieve the purpose of reducing vibration.