June 2018 443 diagram of absolute steam velocities c, relative steam velocities w, rotor rotational velocity u, axial forces f x, and thrust forces f y over the stages in one curtis wheel steam turbine. Inlet velocity triangle and outlet velocity triangle are drawn here in following figure. 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. Its modern manifestation was invented by charles parsons in 1884 the steam turbine is a form of heat engine that. The project was based on an existing impulse turbine, a onestage turbine set in an organic rankine cycle with the working fluid being r245fa. Various methods of loss calculation were explored in the search for a. The system design will be veri ed using a simulation environment that can model the behavior. The static pressure decreases in the nozzle with a corresponding increase in the absolute velocity. If the relative velocity at exit is reduced by friction to 80 % of that at inlet, estimate the axial thrust, diagram power and diagram efficiency. The basic theory behind daniel liquid turbine meters is relatively simple.
Impulse and reaction turbines turbines machines fluid. The velocitycompounded impulse turbine was first proposed by c. The difference in the operating head can be extra simply controlled in francis turbine than in the pelton wheel turbine. Impulse turbine and reaction turbineprinciple, working. Impulse turbines singlerotor or multirotor are simple stages of the turbines. Velocity triangles in turbomachinery linkedin slideshare. The upper portion represents the inlet condition of steam and lower portion represents the outlet portion of steam. The water which is not durt free can cause extremely rapid wear in a high head francis turbine.
Applications of steam turbines power generation transport 4. Estimate also the axial thrust and diagram efficiency b. If the tailrace runs downhill, there is a corresponding loss of headthe wheel setting should have been lower. The conversion is generally accomplished by passing the fluid through a system of stationary passages or vanes that alternate with passages consisting of finlike blades attached to a rotor. If the speed of turbine is too low, the speed increaser must be used to increase the speed.
Analysis of steam turbines for feed water pumps on lng ships icts 2018 portoroa, 14. That is, the blade pushes and turns the fluid in the direction of the blade motion, thereby doing work on the fluid. Also, there are some disadvantages of francis turbine and those are listed below. Apr 06, 2010 lecture series on applied thermodynamics for marine systems by prof.
A turbine was investigated by various methods of calculating its efficiency. Influence of reaction on totaltostatic efficiency with fixed values of. Velocity triangles example velocity triangles example april 12, 2012 mechanical and aerospace engineering department 2. Very simple kaplan turbine design durham university. The program includes tipturbine velocity diagram determination, blade row loss analysis, partial admission, and turbinetofan leakage. Equation 4 is often referred to as the diagram work per unit mass flow and hence. Dec 17, 2019 the pelton wheel or pelton wheel turbine is a tangential flow impulse turbine used for high heads of water. Design and analysis of a kaplan turbine runner wheel. Each stage consists of a nozzle and blade row where the kinetic energy of the jet is absorbed into the turbine rotor as useful work. Assume, it creates at an angle a to the tangent of. Definition a steam turbine is a prime mover in which the potential energy of the steam is transformed into kinetic energy and later in its turn is transformed into the mechanical energy of rotation of the turbine shaft. 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. Lec11 basic concept of turbine, velocity diagram youtube.
Velocity diagram and mollier diagram for a zero reaction turbine stage. Fundamentals of fluid mechanics chapter 12 pumps and turbines. Then enters the moving blades where its direction of flow is. How to draw a velocity triangle for various pumps or turbines. The velocity diagram at inlet and outlet from the rotor is shown in fig. Stewart efficiency characteristics iii terms of velocity diagram parameters the aerodynamic design of axialfl. It is a type of tangential flow impulse turbine used to generate. Hydraulic efficiency this is the efficiency with which water power is converted into diagram power and is given by.
The energy available at the inlet of the turbine is only kinetic energy. Oct 24, 2016 in this article we will study about the pelton wheel or pelton turbine working, main parts, application with diagram. In a vertical francis turbine, the runner speed is 380 r. The angular rotational velocity of the turbine rotor is directly proportional to the fluid velocity through the turbine. Velocity diagram for axial flow turbines watch more videos at videotutorialsindex. After that it entering a curved blade and leaving the nozzle at c. What is velocity and pressure compounding in impulse turbine. Assume, it creates at an angle a to the tangent of the wheel with a velocity v 1 which is the absolute velocity of steam. Curtis to solve the problems of a singlestage impulse turbine for use with high pressure and temperature steam. Francis turbine variation in the operating head can be more simply controlled.
Steam consumption of steam turbine is depending to required output power and efficiency of. The air that leaves the moving blades enters the next set of nozzles where the enthalpy decreases further, and the velocity is. Early turbine examples are windmills and waterwheels. The velocity compounded impulse turbine was first proposed by c g curtis to solve the problem of single stage impulse turbine for use of high pressure and temperature. Its modern manifestation was invented by charles parsons in 1884. Another impulse turbine is the pressure compound or ratteau turbine. Example 3 a pelton wheel buckets are square to jet when they are ahead of the normal position a.
Velocity diagram of centrifugal compressor mechanical. The steam turbine is a form of heat engine that derives much of its improvement in thermodynamic efficiency from the use of multiple. Impulse turbine efficiency calculation methods with. That is, the blade pushes and turns the fluid in the direction of the blade motion, thereby doing. The compressors in most gas turbine applications, especially units over 5mw, use axial. Pdf power plant lecture notes chapter4 steam turbine.
Various methods of loss calculation were explored in the search for a method sufficiently accurate to. Compounding of steam turbines is the strategy in which energy from the steam is extracted in a number of stages rather than a single stage in a turbine. Lecture series on applied thermodynamics for marine systems by prof. Thermal engineering pdf of rk rajput for mechanical. 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. A steam turbine is a device that extracts thermal energy from pressurized steam and uses it to do mechanical work on a rotating output shaft. Mechanical efficiency this is the efficiency with which the diagram power is converted into shaft power. Impulse turbine efficiency calculation methods with organic. Steam turbines, turbine blades, velocity diagrams, impulse, reaction. Very simple kaplan turbine design grant ingram 30th january 2007 nomenclature b blade height g gravitational acceleration h head k loss coe. The mechanical efficiency of the pelton wheel turbine decreases faster than the francis turbine. Velocity diagram of centrifugal compressor following figure shown here indicates the velocity diagram of a centrifugal compressor. Theory of turbo machinery turbomaskinernas teori chapter 4.
First, a theoretical design was performed for determining the main characteristics where it showed an efficiency of 94%. The jet glides over the inside surface and leaves the blade at d. The program includes tip turbine velocity diagram determination, blade row loss analysis, partial admission, and turbine tofan leakage. A turbine is a turbomachine with at least one moving part called a rotor assembly, which is a shaft or drum with blades attached. The system design will be veri ed using a simulation environment that can model the behavior of the test loop under a range of operating conditions. A reaction turbine has rows of fixed blades alternating with rows of moving blades. The velocity compounded impulse turbine was first proposed by c. The steam expands first in the stationary or fixed blades where it gains some velocity as it drops in pressure. Moving fluid acts on the blades so that they move and impart rotational energy to the rotor. The torque and hence the power is proportional to the change in the tangential component of the absolute velocity. Pressure and velocity of steam across nozzle and blades in impulse and reaction.
Design of cross flow turbine and analysis of runners. The velocity diagram of a 50% reaction is symmetrical, and, for the maximum utilization factor, the exit velocity v 2 must be axial. In this turbine, the work is broken down into various stages. The majority of the francis turbines are inward radial flow type and most preferred for medium heads. In a reaction turbine compounding can be achieved only by pressure compounding. The leaving velocity and exhaust loss from a steam turbine may be likened to the tailrace loss of a water wheel. State briefly the reasons for fitting a draft tube to a reaction turbine and sketch three common types. The pelton wheel or pelton wheel turbine is a tangential flow impulse turbine used for high heads of water.
The turbine rotor then extracts work from the flow by removing the kinetic energy associated with the swirl velocity. The appropriate velocity triangles are shown in figure 12. How to draw a velocity triangle for various pumps or. The absolute velocity is then reduced in the rotor, but the static pressure and the relative velocity remain constant. Turbine, any of various devices that convert the energy in a stream of fluid into mechanical energy. From the diagram w 1 v 2, the angles of both the stationary and rotation blades are identical. The steamturbine expansion line on the mollier diagram. The method in which energy from steam is extracted in more than single stage is called compounding.
The pelton wheel turbine is invented by lester allan pelton, an american engineer. The inlet velocity triangle the outlet velocity triangle at the inlet there is no component of absolute velocity in the direction of rotation. The curtis stage turbine, as it came to be called, is composed of one stage of nozzles as the singlestage. Francis turbine diagram, working, parts, advantages. The conversion is generally accomplished by passing the fluid through a system of stationary passages or vanes that alternate with passages. It is a hydraulic turbine which is used in most of the hydroelectric power plant to generate electricity. The inward flow turbine has many advantages over the outward flow turbine as listed below. But it is necessary to consider not only the force of the water which strike the runner, but also own weight of the runner.
Pelton turbine working, main parts, application with diagram. The pressure energy at the inlet and outlet of the turbine is atmospheric. Jet ratio 12 in most casescalculate, d nozzle diameter. Design of a test loop for performance testing of steam.
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