Capacity Increasing Transformation And Performance Prediction Of Flume Propeller Turbine

Flume propeller turbine is widely used in small-scale rural hydropower stations,and it is common that the economic benefit of power generation is poor due to the problems of the turbine.In the past 10 years,the transformation of old power station has been carried out in full swing,but the Flume propeller turbine has not attracted the attention of relevant departments due to its small single capacity and poor economic benefits,and its transformation has almost become a dead angle that is not paid attention to.The economic,simple and reasonable way to carry out the transformation of this kind of units has the social benefits of energy conservation and emission reduction,at the same time,can improve the economic benefits of small hydropower in rural poor areas.The ZD560-LM-100(φ=0°)turbine of xiyinghe hydropower station has failed to perform effectively for many years in Wuwei,Gansu Province,due to the consistency between the hydraulic parameter of the power station and that of the turbine caused by the mistaken choice in the initial design of that power station.The best transformation plan is to replace a new runner that matches the runner size of the turbine and the hydraulic parameters of the power station.However,it is impossible to find a suitable runner that can meet both requirements in the existing runner profile.Due to the poor economic indicators of small hydropower in rural areas,it is impossible to entrust Dongdian or Hadian,which is capable of developing new runner,to undertake the high cost of R&D and transformation.For this reason,a special runner is designed by the singularity distribution method,which matches the runner size of the turbine and the hydraulic parameters of the power station.The model test cost of hydraulic turbine is very high,so it is impossible for small power station to carry out special model test.Nowadays,CFD technology is becoming more and more mature and widely used in engineering practice.It is worth trying to use CFD technology to design and simulate rural small hydropower turbine components,and qualitatively guide and evaluate the transformation scheme based on the results.In this paper,four typical operating points is selected(small flow operating point,smaller flow operating point,optimal operating point and maximum opening operating point).In FLUENT,the standard k-ε turbulence model and SIMPLEC algorithm are used for numerical simulation to obtain the flow information of each component of the turbine in each operating condition,and the law of the efficiency and output of the turbine changing with the opening of the guide vane is given.After transformation,the flow pattern distribution of the turbine is reasonable,which conforms to the flow characteristics of the axial-flow fixed pitch turbine.The flow velocity and pressure in the water guide mechanism are evenly distributed along the circumference,which is beneficial to the stable operation of the unit;The pressure transition on the blade surface is smooth,and the low pressure area near the water outlet,especially the suction surface,has a large range but a small value,which meets the requirements of cavitation performance;The flow condition of draft tube is uniform and stable under the optimal condition,the overall streamline is smooth,and the hydraulic performance is excellent.For the runner model developed by "tailor-made" type of the power station,under the rated parameters of the power station,the output reaches 163 kw and the efficiency reaches 80%,which meets the requirements of capacity expansion and transformation of the power station.It shows that it is feasible to develop the runner by using the singularity distribution method and guide the capacity expansion and reconstruction of the small hydropower station in rural areas with the simulation results of the fluent flow field.