Tm pdf notes unit 6 mech branch downloads smartworld. However, the exit velocity is axial in kaplan runner, while it is the radial one in all other runners. Reaction turbine 2 iii steam turbine operating range 2 3. The force on the vane due to the change in velocity of the fluid is f m. But for smooth flowing of the steam while existing, it creates an angle of. If the tailrace runs level there is the loss of velocity head only, which may be small if the crosssectional area is gen. Velocity triangle for reaction turbine,part6,unit2. It is an inwardflow reaction turbine that combines radial and axial flow concepts francis turbines are the most common water turbine in use today. The jet makes an angle of 30o with the direction of motion of vane at inlet and leaves at an angle of 90o to the direction of motion of vane at outlet. Application of variable speed operation on francis turbi nes. What is the difference in velocity triangles of impulse and. Such a turbine would be an imaginary one and is called specific turbine. Download scientific diagram velocity triangle at the section s2, downstream the. Turbo machines vtu notes pdf tm pdf vtu smart world.
Velocity triangles free download as powerpoint presentation. Extract energy from the fluid the fluid does work on. Pelton wheel turbine working with animation in hindi. Francis and kaplan turbines, constructional details, velocity triangles, power andefficiency calculations, degree of reaction, draft tube, cavitation in turbines, principlesof similarity, unit and specific speed, performance characteristics, selection of waterturbines. When designing a turbine, velocity triangles are crucial for determining the. The francis turbine was developed by an american engineer james bichens francis around 1855. Specific speed of a water turbine in the speed at which a geometrically similar turbine would run if producing unit power 1 kw and working under a net head of 1 m. Hence, these are the parameter changes that has to be incorporated in converting a francis turbine to kaplan turbine. Fluid machinery nme021 download engineering lecture. Francis turbine is the most common type of turbine in practice, which presents a sidebyside design of generator.
Free vortex whirl distribution results in highly twisted blades and is not. Hydropower turbines are in two types as impulse and reaction where kaplan turbine is a reaction type which was invented in 19. Francis turbine runner to analyze the static stress characteristics in the francis turbine runner at various operating points. Velocity triangles may be drawn for both the inlet and outlet sections of any turbomachine. The fluid pressure is atmospheric throughout and the velocity is constant except for a slight reduction due to friction. To satisfy large power demands, very large volume flow rates need to be accommodated in the kaplan turbine, i. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Francis turbine free download as powerpoint presentation. Examples losses in francis turbines npsh main dimensions. Here you can download the turbo machines vtu notes pdf tm pdf vtu of as per vtu syllabus. Losses in francis turbines npsh main dimensions francis turbines. Steam turbine 1 content chapter description page i purpose 2 ii steam turbine types 2 2. Turbines are sometimes differentiated on the basis of the type of inlet flow, whether the inlet velocity is in axial direction, radial direction or a combination of both.
Vu1, vu2 tangential component of absolute velocities at inlet and outlet. The kaplan turbine is an inward flow reaction turbine, which means that the working fluid changes pressure as it moves through the turbine and gives up its energy. The francis turbine is a type of water turbine that was developed by james b. The nps institutional archive reports and technical reports all technical reports collection 196404 radialinflow turbines vavra, m. Pelton turbine velocity triangles, design parameters, maximum efficiency. Fundamentals of fluid mechanics chapter 12 pumps and. Computer methods are introduced in the main text and a key chapter on. For generation of electricity in thermal power plants, steam turbines are used coal fuel oil or nuclear power provides the primary source of energy. Hence velocity diagram for francis turbine is shown below.
Velocity triangles in fluid mechanics and machinery. That is, the blade pushes and turns the fluid in the direction of the blade motion, thereby doing work on the fluid. One the threshold is exceeded, automatic trip of turbine takes place. The video gives you the basic concepts of francis turbine along with its vector diagram. One such way of reducing volume flow in the turbine, for reduced power level, is to reduce stator throat area. Guide vanes in francis turbine technical report pdf. Efficiency of kaplan turbine is higher than francis turbine. Hydraulic turbines may be defined as prime movers that transform the kinetic energy of the. General differences between francis and kaplan turbines. H thakkar3 1,2,3assistant professor 1,2,3department of mechanical engineering 1,2,3sankalchand patel college of engineering, visnagar, gujarat n. Figure 3 turbine runner blades at high left and low right specific speed pddd gq h 1 specific speed can be expressed using turbine design power.
Very simple kaplan turbine design durham university. As a spiral casing is stranded, the runner is not simply available. Development of a 1d performance prediction model for pumps as turbines. Compressible axialflow, mixedflow, radialflow geometry single stage. Velocity defects and the increase of turbulence generated by the turbines in. G, india abstracta peltonwheel impulse turbine is a hydro. Mean diameter of the rotor is 690 mm, it rotates at 4500 revolutions per minute. Introduction a turbine is a rotary mechanical device that extracts energy from a fluid flow and converts it into useful work.
V f1 v f2 and is equal to that at the inlet to the draft tube. The inlet velocity triangle the outlet velocity triangle at the inlet there is no component of absolute velocity in the direction of rotation. Velocity triangle for reaction turbine,part6,unit2,dynamic of machine. Design and analysis of a kaplan turbine runner wheel. Figure 3 velocity triangle v1, v2 absolute velocities at inlet and outlet. Parametrical and theoretical design of a francis turbine runner with the help of computational fluid dynamics. Herewith we have shared the important gate civil engineering notes pdf for the topic of velocity triangles and specific speed of pumps and turbines. Velocity triangles turbine dynamics mechanics free 30. Using the euler turbine equation, emev w1 u 1, where e is the energy transfer to the rotor per unit mass of the fluid. Francis in lowell, massachusetts, mill city usa operate in a water head from 10 to 650 meters 33 to 2,3 feet and are primarily used for. They operate in a water head from 40 to 600 m to 2,000 ft and are used primarily for electrical power. Rather, the simpler geometry provides for a tutorial to turbomachinery analysis in openfoam 11. To determine the specific speed, turbine design power is calculated as seen in equation 1.
The velocity triangle at inlet and outlet of the francis turbine is drawn in the same way as in case of inward flow creation turbine. Francis turbine diagram, working, parts, advantages. Water particle water from spiral casing r a d i a l r a d a l runner guide ivanes runner guide vanes v i e w v e w andi stay vanes and stay vanes 16. A guide vane cascade is developed for the study of flow in the distributor of a low specific speed francis turbine. Turbo machines vtu notes pdf tm pdf vtu of total units. How to draw a velocity triangle for various pumps or. Evolution from francis turbine to kaplan turbine wikipedia. How to draw a velocity triangle for various pumps or turbines. To get more accurate result we should put more operating points during analysis. A jet of water having a velocity of 40 ms strikes a curved vane, which is moving with a velocity of 20 ms. If the tailrace runs downhill, there is a corresponding loss of headthe wheel setting should have been lower.
The inlet is a scrollshaped tube that wraps around the turbines. Velocity and pressure measurements are done with reynolds number 1. This causes the turbine to operate at reduced levels of spe cific speed. The real values of critical speeds should be measured at. Download scientific diagram velocity triangles in turbine mode. According to the newtons second law of motion,the direction of force in the blades, work done in the direction of motion of the blades, mathematically, axial thrust on the wheel is the velocity difference between inlet and outlet steams flow. For a 50% reaction turbine, the velocity triangles are symmetrical and. Velocity triangles example velocity triangles example april 12, 2012 mechanical and aerospace engineering department 2. Velocity triangles for turbine and compressor design. Francis turbine velocity triangles, design parameters, runner shapes for different blade speeds. Usually the flow velocity velocity perpendicular to the tangential direction remains constant throughout, i. In this video i have explained inlet and outlet velocity diagram of pelton wheel turbine. Velocity triangle for francis turbine,part 9,unit 3,turbo 4b engineers.
Based on the velocity triangles at the entrance or exit. The kaplan turbine is a water turbine which has adjustable blades and is used for low heads and high discharges. Water enters the runner of the turbine in the radial direction and leaves the runner in the axial direction. The velocity components are normalised by turbine spouting velocity 2ghfor comparison with respect to common input energy. In zero degree laval steam turbine stage 2 kgs steam enters at a temperature of 280 c, pressure 8 bar and at 60 ms, leaving it by a pressure of 4 bar. The picture shows combined velocity triangle of steam turbine.
The water which is not durt free can cause extremely rapid wear in a high head francis turbine. The geometry of this turbine, though based on a the gamm francis turbine, does not represent any actual turbine in operation. Very simple kaplan turbine design grant ingram 30th january 2007 nomenclature b blade height g gravitational acceleration h head k loss coe. Velocity triangles in turbomachinery linkedin slideshare.
A big radial expansion of the section between inlet and outlet of a pure mean mass flow axial turbine in otherwise action turbine gibe you a typical reaction triangle. Turbines are used in boat propulsion systems, hydroelectric power generators, and jet aircraft engines. Also, there are some disadvantages of francis turbine and those are listed below. Gas with an absolute velocity c 1 making an angle a 1, angle measured from the axial.
From inlet velocity triangle, vw1 v1 assuming no shock and ignoring frictional losses through the vane, we have vr1 vr2 v1 u1 in case of pelton wheel, the inlet and outlet are located at the same radial distance from the centre of runner and hence u1 u2 u from outlet velocity triangle, we have vw2 vr2 cos u2 v1 ucos u. Given a swirlfree velocity profile, as well as a turbine discharge value, the. Flow measurements around guide vanes of francis turbine. To exemplify this, the flowhead relation for a reversible pump turbine in turbine mode is quite different from a francis turbine, which has different geometries even if main dimensions are the same.
Simulation and discussion of models for hydraulic francis. Download pdf, 399kb we will take strict action on publishing above pdf to another website. Modern francis turbine is a mixed flow type turbine i. Jet ratio 12 in most casescalculate, d nozzle diameter. The vector nature of velocity is utilized in the triangles, and the most basic form of a velocity triangle consists of the tangential velocity, the absolute velocity and the relative velocity of the fluid making up three sides of the triangle.
Total 11 points, which including the highest head 79m, and the lowest head 51 m. It is also affected by guide vane opening as it is higher at low guide vane. Pdf day 25 velocity triangles and specific speed of. Velocity defects and the increase of turbulence generated by the turbines in a wind farm usually cause a reduction in power generation. Velocity triangle for francis turbine,part 9,unit 3,turbo. Above 600 rpm rotor relative vibrations should be monitored. Application of variable speed operation on francis turbines. The ratios are made clear in the velocity triangle. Velocity triangle in a pelton wheel pushpendra pathak.
One interesting observation that is made is if the two characteristics from the euler equation model and the valve substitution model are plotted. Velocity triangles turbine physical sciences free 30. Svartisen p 350 mw h 543 m q 371,5 m s d 0 4,86 m d 1 4,31m d 2 2,35 m b 0 0,28 m n 333 rpm. His design is extremely flexible and can be tailored to different head heights and flow rates. This v r2 can be obtain by subtracting the v and v 2 and it create some angle f 1. Francis turbine is a mixed hydraulic turbine the inlet velocity has radial and tangential components while the kaplan turbine is an axial hydraulic turbine the inlet velocity has only axial velocity component. It is explained in easiest terms so that every one can understand the concept. Turbine speci c speed concepts the turbine speci c speed is a quantity derived from dimensional analysis.
The efficiency of a turbine is highly influenced by its runner wheel and this work aims to study the design of a kaplan turbine runner wheel. The turbine is located between the highpressure water source and the lowpressure water exit, usually at the base of a. Abstract the goal of the present thesis is initially to determine if the ideal gas model is valid for the modelling of the refrigerant r245fa for an orc expansion in a radial turbine. The moving blades are running at horizontal direction with a tangential velocity v and v 2 the absolute velocity of steam leaving of moving blades create an angle.
The following list shows the velocity triangles for the inlet side of the rotor. Pdf parametrical and theoretical design of a francis. Difference between francis and kaplan turbine pdf 23. The leaving velocity and exhaust loss from a steam turbine may be likened to the tailrace loss of a water wheel. Since the energy in the steam is represented by the pressure heat energy and velocity kinetic energy, the conversion and transfer of energy in the blading can be visualized. Velocity triangle at the section s2, downstream the runner.
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