Numerical Study On Spacing And Blade Optimization Of Semishielded Resistance Turbine

The development of human society is accompanied by the change of energy utilization.From the initial coal,oil and gas resources to today’s nuclear energy,tidal energy and other clean energy,these energy with the progress of human science and technology has been different degrees of exploitation and utilization.Nowadays,with the decrease of nonrenewable energy,people pay more attention to wind energy,tidal energy and other renewable energy.Among them,tidal current power generation device is widely studied and applied by many researchers.The main device of tidal current power generation is hydraulic turbine.According to the mechanical characteristics of hydraulic turbine,it can be divided into resistance type and lift type.Firstly,in this paper,several kinds of lift type turbine and resistance type turbine are introduced.Secondly,their mechanical characteristics and advantages and disadvantages are compared and analyzed.Based on the previous research,the mechanical and power characteristics of vertical resistance blade were studied from the aspect of blade shape parameters and layout.In this paper,SST k-omega turbulence model and sliding grid method are used to simulate the hydrodynamic performance of semi-shielded tidal turbine.In order to verify the effectiveness of turbulence model and sliding grid method,the existing turbine experimental results are used to verify the turbulence model and grid method.By comparing the numerical simulation results with the experimental data,it is found that SST k-Omega turbulence model and sliding grid method are suitable for the numerical simulation of rotating impeller.For the semi-shielded vertical shaft resistance turbine,tidal current speed,impeller speed,blade spacing and shroud coverage of duct are main factors to affect generating power of hydraulic turbine.In order to understand the influence of these variables on turbine generating power,the control single variable principle is used to study these parameters.Finally,some rules are found through a lot of data comparison.At the same time,these results show that the end geometry of turbine blade can greatly affect its generating power.In order to solve this problem,a winglet structure is added at the end of the blade.Through the simulation results,it is found that the turbine with negative angle winglet has higher generation efficiency.These results can provide reference for the commissioning,installation and geometric parameter optimization of the semi-shielded turbine.