Research On The Optimized Design Of The Hydroturbine Used In Industrial Cooling Towers

A hydroturbine used in an industrial cooling tower recycles the surplus energy of the circulating water system,saving a great many of electric energies each year.Its mechanical efficiency matters the amount of energy conservation a lot.The optimization of runner blade profile,rational design of volute and vane,and putting in full use of draft tube for recovery kinetic energy are studied to improve the efficiency.In this article,the design method and optimization strategies for the turbine were studied,and also its unique performance,and means of improving its efficiency.In the paper,the primary design of runner was carried out by one-dimensional method aided by CFD technology.The response surface optimization method bases on the function relating efficiency with blade shape parameters.A random experiment was conducted to produce data of varied blades,whose efficiencies were gotten in CFD technology.Blades data and their efficiencies were used to simulate a function for searching optimal parameters for the most efficient runner.The effects of various blade parameters on runner efficiency were studied by multivariate statistical analysis.The design of vane aided to provide circulation and low-speed in volute was chosen.The draft tube having a larger taper can recover kinetic energy as much as possible.The performance of the Francis turbine in five chosen working conditions is calculated after its characteristics were analyzed,which are the series characteristic in cooling towers,the proportional characteristic of its speed and flow,and the selfsimilarity of its working condition.The experiment results verified the rationality of the design method for the runner and the diversion parts.Rules of the turbine’s head,power and efficiency changing on various working conditions were studied in simulation results,considering its application environment.Because of its self-similarity of working conditions,its efficiency kept nearly unchanged when power and head changed rapidly.It was finally found that the speed-efficiency curve and the flow-efficiency curve of the turbine approximately fit cubic curves.