Numerical Simulation And Loss Mechanism Of Six Nozzle Pelton Turbine

With the increasing use of electricity worldwide,the power industry is facing the opportunity of high-speed development.Hydraulic power generation is widely used because of its advantages of clean resources,rich and sustainable development.The pelton turbine is widely used as the main equipment to use high water head.In order to improve the force of the pelton turbine,the newly designed pelton turbine generally uses multiple nozzles,and the multi nozzles mean that the flow is more complex and more difficult to analyze.The six nozzle pelton turbine is a multi nozzle pelton turbine which has been used more now.There are few studies on its total channel loss analysis.In view of this,this paper analyzes the flow process inside the six nozzle pelton turbine,finding the flow loss and causes in the operation,and provideing the basis for optimizing and improving the force and efficiency of the multi nozzle impingement turbine.The specif ic research contents are as follows:1.Explore the loss principle of water supply mechanism of pelton turbine,analyze the influence of opening and head change on the loss of water supply mechanism and the change of pressure and speed inside the water sup ply mechanism,and find out the internal loss and cause of the water supply mechanism.2.Analyze the influence mechanism of the internal flow state of the feed water mechanism on the free jet,and the shape and internal energy of the free jet are analyzed in detail.3.Using the VOF model to accurately capture the characteristics of the gas liquid interface,through the moment curve,the free jet flow state diagram and the vorticity distribution,the flow process of the free jet impingement wheel is analyzed,and the change law of the bucket moment is obtained.4.Analysis of the internal working process of the runner to find out the bad flow phenomenon affecting the force and efficiency in the working process,and analyze the influence of the opening and head change on the bad flow in the wheel,and get the cause of the bad flow phenomenon in the wheel.The results show that:the energy loss of water supply mechanism of the six nozzle pelton turbine is mainly concentrated in the nozzle part,the energy loss of the nozzle part is greatly influenced by the opening degree,but the relationship with the head is weak,the loss of the bifurcation pipe is relatively small,and the loss between the six bifurcating pipes is different,and the fluid flow is close to th e direction of the flow through the bifurcate pipe.The inside of the fork produces whirlpools,causing the inner pressure of the bifurcate pipe to be lower than the lateral pressure and the inner velocity is lower than the lateral velocity;the vortex continues to develop downstream to change the shape of the free jet;the 21 bucket has the same output characteristics,and there is only a phase difference between each other,and there are 7 different states of water at the same time.There are mainly three kinds of adverse flow phenomena in the process of free jet impinging runner.The change of opening and head will affect three kinds of bad flow.