Design And Hydrodynamic Performance Of Micro Head Flow Turbine

Water flow energy is a kind of green and pollution-free renewable energy.Its development and utilization is of great strategic significance.In the fourteenth five year plan,the state emphasizes the development of hydropower energy.At present,the total amount of hydropower generation in China is large,but a large number of micro head resources have not been effectively utilized.At the same time,the water head in the micro head water area is low,and the flow velocity is small.Affected by the boundary effect,the flow velocity gradient phenomenon will appear.The flow velocity and velocity gradient affect the start-up of the turbine and the collection of flow energy to a certain extent,which directly leads to the problems of low power generation and high start-up velocity of the turbine.In response to the national renewable energy development strategy,this paper designs a turbine suitable for micro head water area and studies its hydrodynamic performance.This paper proposes a method to change the structure of the turbine to compensate the flow.A collection device is designed on the basis of the deflector to weaken the influence of the velocity gradient on the hydrodynamic performance of the turbine,so as to improve the collection of flow energy of the turbine in the micro head and reduce the starting velocity of the turbine.By comparing the research status of micro head turbine,shroud and impeller at home and abroad in recent years,this paper studies the working principle of shroud and the relevant theoretical basis of impeller design,introduces momentum theory,blade element theory and the type and characteristics of airfoil into the design of turbine blade,and simply deduces the formula of velocity gradient in micro head water area According to the flow gradient and the actual test environment,the structure dimensions of the shroud,the collection device and the impeller are obtained by simple design and analysis,and the three-dimensional model is established by using Solidworks.Using CFD method,using ANSYS Fluent software is used to simulate the hydrodynamic performance of different structures of turbines,analyze the hydrodynamic performance of turbines with uniform and non-uniform flow velocity,and analyze the blade pressure,flow field distribution and turbine position under non-uniform flow velocity,so as to further study the hydrodynamic performance of turbines with different structures,The test results of different structures of turbines in natural flow are consistent with the numerical simulation.In this paper,through the analysis of the hydrodynamic performance of different structure turbines,the performance of different structure turbines under different working conditions is preliminarily shown.It also proves that the method of using structure to compensate flow in micro head water area is feasible.It provides methods and reference basis for improving the collection of flow energy and reducing the influence of velocity gradient on the hydrodynamic performance of turbine in micro head water area.