Monday, September 30, 2019
Hydraulic Turbines
M.V. Sai Ram AP17110020010 Branch: ECE Here some of the problems I faced in the research of the hydraulic turbines. Effect of blade numbers on slip factor of hydraulic turbine: The change curve of slip factor is shown when the blade numbers change at the design condition . With the increase in blade numbers, the slip factor within centripetal impeller is gradually increased, and the rate of increase is gradually decreased. Therefore, with the increase in blade numbers, the slip value within centripetal impeller is gradually decreased. The main reason is that function of restriction of blade gradually strengthens for fluid with the increase in blade numbers; it leads to the slip value within centripetal impeller being gradually decreased.Effect of entrance width of centripetal impeller on slip factor of hydraulic turbine. The hydraulic efficiency of a turbine excludes friction losses on the outside of the runner, leakage loss of water that does not pass through the runner blades and mechanical friction losses. The hydraulic efficiency of a well-designed turbine is 98-99%.Can interaction occur between the electric power system and the hydraulic system for this frequency range.Velocity and pressure are highly sensitive to the operation conditions. It has been found that the stresses in the trailing edge of the runner blade near the crown reach a critical state in all operating points.Abstract:A set of empirical has been developed which defines the peak efficiency and shape of the efficiency curve for hydraulic turbines as a function commissioning date for the unit ,rated flow, runner speed, and throat or impulse turbine jet diameter.The aim of this investigation was to develop an environmentally friendly nano-hydraulic turbine utilizing waterfalls. A model of an impulse type hydraulic turbine constructed and tested with an indoor type waterfall to arrive at an optimum installation condition. Effects of an installation parameter, namely distance between the rotor and the waterfall on the power performance were studied. The flow field around the rotor was examined visually to clarify influences of installation conditions on the flow field. The flow visualization showed differences of flow pattern around the rotor by the change of flow rate and rotational speed of the rotor.Every single turbine is custom-designed specifically to meet the requirements of a hydroelectric power plant. Performance of a designed turbine is validated, to some extent, by computational fluid dynamics simulations. Field performance testing of hydraulic turbines is undertaken to define the head-power-discharge relationship that identifies the peak operating point of the turbine. This relationship is essential for the efficient operation of a hydraulic turbine.The art of hydraulic turbine design never stands still but always progresses. In recent years major emphasis has been on the materials of construction and on such features of design as will reduce maintenance work and costly outages in the field.LimitationsHydro power plant or we can say that hydraulic turbines are widely used from the last decades. It is an efficient renewable energy source. There are many up and downs. Hence there Some limitations as shown in below,It is a renewable energy source. Water energy can be used again and again.the running cost of turbine or less compare to other.It has high efficiency.It does not pollute environment.It is to maintain.Importance: Here the importance of hydraulic turbine and their uses Turbines are used for hydropower generation. There are basically two types of hydraulic turbines, the first one is impulse and the second one is reaction type turbines. Impulse turbinesThe use of hydraulic turbines for the generation of power has a very strong historical tradition. The first truly effective inward flow reaction turbine was developed and tested by Francis. Modern Francis turbines have developed into very different forms from the original, but they all retain the concept of radial inward flow(Aradag,2018)Hydraulic turbines are not only used to convert hydraulic energy into electricity but also in pumped storage schemes, which is the most efficient large-scale technology available for the storage of electrical energy. Separate pumps and turbines or reversible machines, so called pump turbines, are used in such schemes.(Gordon,2010)The efficient application of advanced CFD is of great practical importance, as the design of hydraulic turbines is customtailored for each project. a CFD-based design method is used to obtain the runner blade shape and characteristics. The hydraulic turbine used to convert the potential energy of water to mechanical energy. Flowing water is directed on to the blades of a turbine runner, creating a force on the blades. Since the runner is spinning, the force acts through a distance (force acting through a distance is the definition of work). In this way, energy is transferred from the flowing water to the turbine.(Guangtai,2015) In Francis turbines, water enters the turbine runner in the radial direction and leaves axially. The main parts of a Francis turbine are spiral case, stationary vanes, guide vanes, runner, and draft tube, as shown in Figure 1. The flowrate and accordingly the produced power are adjusted by the guide vanes. The spiral case regulates the velocity profile entering the turbine, whereas the stationary vanes provide the mechanical strength.3 The most critical part of the turbine, runner, converts the water energy to mechanical energy and rotates the generator(Aradag,2018)A new design of main bearing and carbon seal ring for vertical-shaft Francis turbines provides a bearing immersed in an oil bath covering about one-third of its vertical length. Properly slanted and shaped oil grooves provide for self lubrication, thereby eliminating the troubles usually associated with mechanical lubrication. (Rheingans,1948)Research:The research I have done based on the hydraulic turbines and power plant design. The goals in the development of an optimal water turbine with high efficiency. Can interaction occur between the electric power system and the hydraulic system for this frequency range. Hydraulic turbines of hydroelectric power plants are designed and manufactured according to the head and discharge parameters of a specific plant. Each hydroelectric power plant is different and requires a custom-designed turbine for better performance.Francis-type hydraulic turbines : In Francis turbines, water enters the turbine runner in the radial direction and leaves axially. The main parts of a Francis turbine are spiral case, stationary vanes, guide vanes, runner, and draft tube. The flowrate and accordingly the produced power are adjusted by the guide vanes. The spiral case regulates the velocity profile entering the turbine, whereas the stationary vanes provide the mechanical strength.The most critical part of the turbine, runner, converts the water energy to mechanical energy and rotates the generator. The principal feature of a reaction turbine that distinguishes it from an impulse turbine is that only a part of the total head available at the inlet to the turbine is converted to velocity head, before the runner is reached. Also in the reaction turbines the working fluid, instead of engaging only one or two blades, completely fills the passages in the runner. The pressure or static head of the fluid changes gradually as it passes through the runner along with the change in its kinetic energy based on absolute velocity due to the impulse action between the fluid and the runner. Description Reference List: Brekke,H.(January 08,2010).Performance and Safety of Hydraulic Turbines,12(1),1-11,Beijing, China. Retrieved: 9 March 2018http://iopscience.iop.org/article/10.1088/1755-1315/12/1/012061Gordon,J.L.(December 18,2001).Hydraulic Turbine Efficiency,28(2),238-253,CanadianJournal of Civil Engineering. Retrieved: 10 March 2018http://www.nrcresearchpress.com/doi/abs/10.1139/l00-102#.Wqgl0ehuZPZGuangtai,S.Xiaobing,L.Junhu,Y.Senchun,M.Jicheng,Li.(Juli,2015).heoretical research ofhydraulic turbine performance based on slip factor within centripetal impeller,7(7),1-9.Retrieved: 11 March 2018https://doi.org/10.1177/1687814015593864Ikeda,T.Tatsuno,k(January 03,2010).Performance of Nano-hydraulic turbine utilizingwaterfalls,35(1),168.Retrieved : 10 March 2018https://www.researchgate.net/publication/222577757_Performance_of_nano-hydraulic_turbine_utilizing_waterfallsKavurmaci,B.Celebioglu,K.Aradag,S.Tascioglu,Y.(June 29,2018),50(3),70-73Model Testing of Francis-Type Hydraulic Turbines . Tobb University of Economics andTechnology, Ankara, Turkey. Retrieved: 7 March 2018https://doi.org/10.1177/0020294017702284Manness,J.Doering,j(March 26,2005).An improved model for predicting the efficiency ofhydraulic propeller turbines,32(5),789-795, Canadian Journal of Civil Engineering. Retrieved:9 March 2018http://www.nrcresearchpress.com/doi/abs/10.1139/l05-029#.Wqh9suhuZPYhttp://ieeexplore.ieee.org/document/6444369/authorRudd, F.O. (July 01,1965).Hydraulic Turbine Setting Criteria,87(3),295-298.Technical Engineering Branch Analysis Branch. Retrieved: 5 March 2018http://gasturbinespower.asmedigitalcollection.asme.org/article.aspx?articleid=1416900
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