Impulse turbine and reaction turbineprinciple, working. In a pelton turbine or pelton wheel water jets impact on the blades of the turbine making the wheel rotate, producing torque and power. Steam turbines have a set of rotating blades and a row of fixed half moon blades. Efficiency, while clearly a consideration, takes a less prominent role than in aircraft turbine design. Ed nelson is a tu rbo machinery consultant based in dickinson, texas. Specific speed governing and limitations of impulse turbine nptel.
Pelton turbine or wheel is an impulsive turbine used mainly for high head hydroelectric schemes. The parts of a steam turbine may be thought of as being in four groupings. Francis turbine works on medium range of specific speed i. Differences between francis and kaplan turbines mech4study. This is why we call this type of turbine as impulse turbines. In this method the steam flow is regulated by opening or closing some set of nozzles of the turbine. Both turbines produced power due to both kinetic energy and pressure energy. Standard deviation for compressive strength of concrete with example pdf. Schematic of impulse and reaction turbines, where the rotor is the rotating part, and. Steam turbine governing is the procedure of controlling the flow rate of steam to a steam turbine so as to maintain its speed of rotation as constant. When steam strikes the moving blades through nozzles called impulse turbine and when it strikes the moving blades under pressure via guide mechanism called reaction turbine. Reaction turbine blading and conditions figure 3 shows, at the top.
The high velocity jet coming out of the nozzle then impinges on a series of buckets fixed around the rim of a wheel. The importance of this method is, the turbine can maintain a constant steady speed irrespective of variation of its load. The pelton wheel is among the most efficient types of water turbines. Elec0047 power system dynamics, control and stability. The impulse turbine is composed of moving blades alternating with fixed nozzles. Steam turbine governing and its mechanism ece tutorials. Being impulse turbine it must run at atmospheric pressure a nd therefore, these are located above the tail race. The steam turbine working principle and theory has been explained in. When the jet of water strikes at the turbine blade with full of its speed, it generates a large force which used to rotate the turbine. Modern steam turbines frequently employ both reaction and impulse in the same unit, typically varying the degree of reaction and impulse from the blade root to its periphery. Pelton turbine used for large water heights 300 m or more 31. Later, impulse turbines were developed which didnt use swirl. Unloaders a typical turbine governing system has two unloaders one activated by low condenservacuum. Steam turbine governing is the procedure of monitoring and controlling the flow rate of steam into the turbine with the objective of maintaining its speed of rotation as constant.
Governing system of gas turbine free download as powerpoint presentation. In the reaction turbine, first the steam flows through the guide mechanism. Automatic generation control and monitoring the mechanism of micro hydro power plant with impulse turbine and synchronous generator conference paper pdf available november 2016 with 874 reads. Nelson turbomachinery consultant dickinson, texas and perryc. This turbine combines the rotational forces of the previously described turbines.
The pelton wheel extracts energy from the impulse of moving water, as opposed to waters dead weight like the traditional overshot water wheel. Different parts and their functions of pelton turbine are as follows. Steam turbine governing system is a method, used to maintain a constant steady speed of turbine. Impulse turbine and reaction turbine nuclear power.
Learn more about design, analysis, working principle and applications of pelton wheel turbine. The impulse generated in this procedure is used to provide the momentum to the blades. Water leaving those wheels typically still had high. Pelton turbine is a tangential flow impulse turbine in which the pressure energy of water is converted into kinetic. Comparison between impulse turbine and reaction turbine. Okay we have discussed pelton wheels first, that is the impulse flow turbine, purely. Read working principle of impulse and reaction steam turbine.
It was discovered in 188 0 by an american engineer lestera. If francis turbine is run below 50 percent head for a long period it will not only lose its efficiency but also the cavitation danger will become more serious 4. Unesco eolss sample chapters thermal power plants vol. Difference between impulse and reaction turbine impulse turbine reaction turbine 1. Low initial cost and simple mechanism makes throttle governing the most apt method for small steam turbines. Pdf power plant lecture notes chapter6 gas turbines. Hydraulic turbines are being used from very ancient times to harness the energy stored in flowing streams, rivers and lakes. Action or impulse type turbines the potential energy of water is converted into pressure and then into kinetic energy by passing through nozzles. Oct 21, 2016 on this channel you can get education and knowledge for general issues and topics.
Kaplan turbine requires high value of specific speed because it is works on low head. Governing of impulse turbines jet engine turbine scribd. A water turbine is a rotary machine that converts kinetic energy and potential energy of water. Use of a small section of a curtis arrangement, typically one nozzle section and two or three rows of moving blades, is usually termed a curtis wheel and in this form, the curtis found widespread use at sea as a governing stage on many reaction and impulse turbines and turbine sets. Schematic diagram summarising the differences between impulse turbine and reaction turbine, where the rotor is the rotating part and the stator is the stationary part of the machine.
Pelton turbine is a tangential flow impulse turbine in which the pressure energy of water is converted into kinetic energy to form high speed water jet and this jet strikes the wheel tangentially to make it rotate. Explain parts and working principle of pelton turbine with neat sketch. Gas turbine governing dynamics and control systems. The runner is a mechanism that converts the hydraulic energy into mechanical power by. On this channel you can get education and knowledge for general issues and topics. Pelton turbine parts, working and design aspects the constructor. The word turbine has been derived from the greek word tyrbe which has the meaning turbulence.
This paper is to design the pelton turbine, its regulating mechanism and speed control system that can develop a power output of 225 kw. There are two basic types of turbines according to the mode of steam. The specific speed is an important factor governing the selection of the. In impulse turbine the steam flows through the nozzle and strike on the moving blades. The highvelocity jets of water hit spoonshaped buckets on the runner. This speed should also conforms to the power supply frequency. Pelton turbine among different types of impulse turbines, pelton wheel is the only turbine beingused at present. In this paper, the turbine used for hydropower plant is the pelton turbine which is one of the impulse turbines.
Impulse and reaction blades can be combined to form an impulsereaction turbine. Governing of impulse turbines free download as pdf file. The flow energy to the impulse turbines is completely converted to kinetic energy before. Each bucket reverses the flow of water and this impulse spins the turbine. Curtis turbine, rateau turbine, or browncurtis turbine are impulse type turbines. The steam turbine training course has been developed to assist in turbine maintenance and turbine operation. With a poor governing system, these smaller, less abrupt, load changes can still result in. In the impulse turbine, the steam is expanded in fixed nozzles and remains at constant pressure when passing over the blades. Turbine speed governing system plz use speakers duration. Comparison between throttling and nozzle governing mechanisms.
The design data are taken from wattwon hydropower in pyin oo lwin, myanmar. Understanding and preventing steam turbine overspeeds by. Impulse and reaction turbine are compared below presented in picture and tabular form. Turbine parameter impulse turbine reaction turbine steam pressure decreases in every nozzle. A pelton turbine develops 2000 kw under a head of 100 m and with an overall. Approval issue module 2347 the turbine governing system. Rocket turbine design emphasizes power density, because of the overriding concern for mass saving. What is the difference between an impulse and a reaction. Pressurevelocity compounding curtis turbine curtis turbine pressurevelocity compounding. Apr 25, 2016 impulse turbine works on the basic principle of impulse. Governing of hydraulic turbine free download as powerpoint presentation. Dahlqvist approved 20121016 examiner damian vogt supervisor jens fridh commissioner contact person 1 abstract a turbine was investigated by various methods of calculating its efficiency.
Specific speed, governing and limitations of impulse turbine. Impulse turbines change the direction of flow of a high velocity fluid or gas jet. The various turbine types have been explained in detail. Write the short notes of governing mechanisms of pelton wheel.
Impulse turbine works on the basic principle of impulse. Now in reaction machines, this is done by this mechanism, i will show you. Steam turbine governing is the procedure of controlling the flow rate of steam to a steam turbine. Specifications tangential flow turbine high head turbine speed and discharge is very less shape of the blade is double hemi sphere efficiency is near about 88% to 98%. Before talking about the differences lets see some similarities 1. California polytechnic state university, san luis obispo. The modern demonstration of turbine was invented by sir charles parsons in 1884. Steam turbines classification, governing equations and. Chaplin encyclopedia of life support systems eolss figure 4.
Many earlier variations of impulse turbines existed, but they were less efficient than peltons design. Impulse turbine basic mechanical engineering benchmark ktu duration. Understanding and preventing steam turbine overspeeds by william e. Steam turbine working principle and types of steam turbine. Pelton turbine among different types of impulse turbines, pelton wheel is the only turbine being used at. It covers the governing system and includes working of the woodward governor type. The force is depends on the time interval and velocity of jet strikes the blades. So this mechanism acts as a speed governing mechanism of pelton wheel. Governing of francis water turbine 111520 the major componentsof the governor mechanism are as under.
Impulse turbine efficiency calculation methods with. Impulse turbine efficiency calculation methods with organic rankine cycle johan e. One of the most popular example of impulse turbine is pelton wheel. Impulse turbine efficiency calculation methods with organic. It operates under v ery high heads upto 1800 m and requires comparatively lesser quantity of water.
In principle, the impulse steam turbine consists of a casing containing stationary steam nozzles and a rotor with moving or rotating buckets. Turbines a turbine is a rotary engine that exerts energy from a fluid flow and converts it into useful work. The fluid power is converted into kinetic energy in the nozzles. Reaction turbine 2 iii steam turbine operating range 2 3. This practice is still commonplace today in marine steam.
H thakkar3 1,2,3assistant professor 1,2,3department of mechanical engineering 1,2,3sankalchand patel college of engineering, visnagar, gujarat n. Turbine is a machine which uses the kinetic energy of fluids and transforms into mechanical energy through a designed mechanism. Generally the range of specific speed varies from 600. The turbine in the operation can be either driven by principle of reaction mechanism or impulse mechanism. The buckets are so shaped that water enters tangentially in the middle and discharges backward and flows again tangentially in both the direction to avoid thrust on the wheel as shown in the line sketch.
He retired fro m amoco oil company, after more than 36 years in. Steam turbine 1 content chapter description page i purpose 2 ii steam turbine types 2 2. In this article, we see about the impulse turbine and reaction turbine principle, working and difference. Steam turbine is the widely use as a prime mover in power plants, refineries, petrochemical plants, food processing plants, power plants etc. Governing system of gas turbine control theory throttle. The variation in load during the operation of a steam turbine can have a significant impact on its performance. Review of optimal selection of turbines for hydroelectric. G, india abstracta peltonwheel impulse turbine is a hydro.
Impulse stages may be either pressurecompounded, velocitycompounded, or pressurevelocity compounded. The methods used for governing of impulse turbines are. Jun 08, 2018 francis turbine works on medium range of specific speed i. The pressurevelocity compounding is a combination of the above two types of compounding. Oct 20, 2016 on this channel you can get education and knowledge for general issues and topics. Impulse turbine and reaction turbineprinciple, working and.
This pdf explains in details about the different types of governing systems being used in gas turbines. Pdf automatic generation control and monitoring the. This turbine used to rotate the generator, which produces electric power. When the steam passes through the stationary nozzles and is directed at high velocity against the rotor buckets. Action or impulsetype turbines the potential energy of water is converted into pressure and then into kinetic energy by passing through nozzles. Types of governing mechanisum for impulse turbine 1needle wheel rod. It consists of a stationary circular wheel on which. This type of governing is suitable for simple impulse turbine and most efficiently in part load conditions. If you do not add any mechanism to changed the driving torque, the speed of the rotor will.
The pelton turbine is a tangential flow impulse turbine. Impulse turbines rotate due to the impact of fluid over the blade, thus rotating the hub. The flow rate of steam is monitored and controlled by interposing valves between the boiler and the turbine. The guide vane mechanism along with the governors provides the regulation of the turbine. The wheelshaped rotating blades sandwich the fixed blades. It is the most renowned example of impulse turbine. A pelton wheel is an impulsetype water turbine invented by lester allan pelton in the 1870s.