Performance Analysis And Technical Transformation Of Tubular Turbine

Low-head hydraulic resource in our country are very rich,with the rapid growth in demand for energy consumption,and conflicts such as supply and demand problems.Reasonable and efficient development low-head resources is become an urgent need for us.Tubular turbine have many advantages such as have big flow, high-speed,high efficiency,wide high efficiency area,compact structure,and simple layout,and so on.By those advantages,tubular turbine is became one of the most economic and suitable types of turbines to develop low-head hydropower resources. As for small hydroelectric stations,there are many advantages:not only non-polluting,low-cost and the renewable energy which is used,but its scattered resource,the small negative impact on the ecological environment,the matured technology,less investment,easy construction.The development of small hydropower,to accelerate the rural electrification and the construction of modernization socialist new countryside,and the promotion of spiritual civilization, and the building of a harmonious society,have significance and important positive role in promoting.However,small hydropower development of low-head hydropower resources,there have still many shortcomings and need for improvement.For example,hydraulic models are few at low-head,and excellent hydraulic models are even less;technical indicators and their performance are also subject to further improved.It difficult for reasonable and effective developing and utilizing for the specific water parameters of water resources.To end,based on the need of reality and engineering,Tubular Turbine is be selected for doing water models develop and performance research,which is one of hydraulic models at low-head hydropower resources.In the text,as for GD008-WZ-140 shaft extension tubular turbine in some hydropower station,there is a serious shortage of effort,vibration,noise and other major problems.After several exploration and testing site,essentially rule out the possibility of electrical and mechanical reasons.Decide to start from the hydraulic analysis.Using the methods and means of CFD numerical simulation,based on the original design parameters,doing numerical calculation and simulation at different angle of blade many conditions to the full port of the turbine.By the analysis and comparison of the results,have a look for the cause of those problems,and to seek a solution.Under different conditions by the flow field calculation and analysis, preliminary indicated the reasons for above problems at operation.The main reasons are both the original hydraulic model selected and the manufacturer exist in defect.Cause the bad flow distribution on runner blade and airfoil.The cascade density from the middle wingspan to the rim of the original blade gradually increasing the level of small.The outlet of guide vane can't meet the inlet of blade, exists negative angle,and resulting in increasing volume loss and water loss, efficiency drop seriously.Manufacturing has also changed the guide vane airfoil. Therefore,the unit at the station with the hydraulic parameters does not reach the rated output,and have vibration and noise at operate.Runner is the component that direct energy conversion in Hydro-electric power unit.The performance of runner basically decide good or bad performance the unit have.So,runner is the heart and the most critical component of hydro-generating unit.Based on that,under the transformation funding of power station project and the restrictions,the main technical can only be carried out against the runner.In the text,based on above problems determine the technical basic idea. The technical is that extend the airfoil of the original blade from middle wingspan to the flange for increasing density cascade;adjust the airfoil head angle and angle of blade and airfoil thickness along the wingspan direction.Do that to make its flow distribution more suitable and the demand for energy conversion.Following the transformation ideas and the development of the implementation program.Based on the simulation results,carrying out blade airfoil repair and reform to the original wood.Through CFD technology,doing numerical simulation, analysis and performance prediction repeatedly.The results showed that the transformation of the program entirely feasible,and carried out blade modify.The runner be installed in the power station,the results show that unit efforts can achieve and exceed the requirements of the original design;vibration and noise significantly reduced,and noise reduce from 95dB to about 83dB,and vibration is also essential to eliminate.It can be seen,not only the transformation of this project is successful;and, more importantly,through the transformation of the actual unit project proved strongly once again:turbo-machinery's blade modification and modification of the method is targeted based on CFD analysis,easily achievemodified or improved's goals;and contribute to station design parameters selection and optimization,as well as the flow components;and has a very high practical value and realistic significance and engineering significance to Hydropower Station update and transform.Although the author has some results in transformation in the wheel and CFD calculations,the most efficient of the runner with the international advanced level in a larger difference;Numerical simulation techniques and methods,particularly,the study of turbulence model lack Etc,there are needing further study,research and promotion.