Study On The Performance Of Francis Turbine With Long And Short Blades Based On Numerical Method

It is found that the long and short blade Francis turbine has obvious advantages in improving the working performance of high head turbine.In order to more widely popularize and apply this new type of turbine,it is necessary to study it in this paper.Object,the numerical simulation technique is used to calculate the whole runway,and the energy characteristics,cavitation characteristics and mechanical properties of the turbine are analyzed according to the calculation results.The main research contents are:(1)Three-dimensional model of turbine full flow channel was established by using SolidWorks,bladegen and other software.The grid model was introduced by using software such as icem and turbogrid.The grid model was introduced into cfx and parameterized and calculated.(2)The flow field distribution and velocity distribution of each flow component under the typical working condition of the turbine are analyzed.It is found that the flow rate is the best in the flow condition,the hydraulic loss is the smallest,the energy characteristic is the best,and the other energy characteristics are poor.The internal flow and pressure distribution of the long and short blade runner and the conventional blade(long blade only)were compared and the energy characteristics of the two turbines were similar.(3)The airfoil pressure distribution and flow state of the turbine runner are analyzed.It is found that the blade head is prone to cavitation under the small flow condition,and the leaf outlet is more prone to cavitation in the middle flow condition and the large flow rate The Compared with the conventional runner,it is found that the cavitation performance of the long and short blade runner is better than that of the conventional(long blade)wheel,which is helpful to improve the study of the cavitation performance of the rotor.According to the generation of vortices in the draft tube,the cavitation in the draft tube is predicted.In the small flow condition and the large flow condition,the cavity cavitation is more likely to occur,and the cavitation is less likely to occur in the middle flow condition.(4)The two-way fluid-solid coupling method is used to calculate and analyze the stress and strain distribution of the turbine runner under various working conditions.The maximum stress of the runner in several working conditions is related to the outlet of the rotor blade At the office.