| The special ultra-low specific speed diagonal flow turbine for cooling tower is a new type of cooling tower turbine.It takes an existing ultra-low specific speed Francis turbine with similar specific speed as the target,and is designed with the help of the equivalent conditions between the special-shaped turbines.Produced an ultra-low specific speed diagonal flow turbine.The runner,as the core component of the hydraulic turbine,plays an important role in energy conversion.The runner blades of the ultra-low specific speed diagonal flow turbine are cantilevered and have no lower ring,which can solve the problem of the excessively flat welding of the Francis turbine.At the same time,compared with the axial flow turbine,the internal flow of the diagonal flow turbine runner has a radial component,which can solve the problem of only the offset inertia force in the axial flow turbine.Therefore,the optimization of the runner is helpful to improve the hydraulic performance of the ultra-low specific speed diagonal flow turbine.Based on the orthogonal test method,this paper selects 5 parameters of the runner inlet diameter1,blade wrap angleθ,blade width B,blade number and blade rotation axis inclination angleδof the ultra-low specific speed diagonal flow turbine to formulate 12 sets of orthogonal test schemes.After range analysis,when efficiency is used as the evaluation index,the order of factors affecting efficiency is blade width B,rotation axis inclination angleδ,runner inlet diameter D1,number of blades,blade wrap angleθ;When the water head is used as the evaluation index,the order of the factors affecting the water head is the inclination angle of the rotation axisδ,the blade width B,the runner inlet diameter D1,the blade wrap angleθ,and the number of blades;The optimal parameter combination is:the runner inlet diameter D1 is 450mm,the blade width B is 40mm,the blade wrap angleθis 4°,the number of blades is 22,and the rotation axis tilt angleδis 45°. |
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