The chance of steam leakage will be more when compared to velocity compounded turbine. The pressurevelocity compounding is a combination of the above two types of compounding. It consists of a rotor and a set of rotating blades which are attached to a shaft and the shaft is placed in the middle of the rotor. Outline of tc4f40 1,000mw steam turbine for 60hz use the design of the tandemcompound 1,000mw steam turbine for 60hz use is based on the tc4f40 700mw steam turbine which has already been operated at the hekinan power plant of chubu electric power co. Pdf power plant lecture notes chapter4 steam turbine. Are you a person willing to work in industrial sectors then logon to steam turbine is a device that extracts thermal energy from pressurized steam and uses it to do mechanical work on a rotating output shaft. What is steam turbine description and characteristics. The rand woodbury illusionworks pdf pressure compounded impulse turbine is also called as rateau turbine, after its. Originally invented as a means of making steam engines more efficient, the compounding of engines by use of several stages. This results in lower or more acceptable steam flow speeds and a better.
Pressure compounding of an impulse turbine is the use of a number of stages of nozzle and blade to reduce progressively the steam pressure. Fundamentals of steam turbine systems principles of operation the motive power in a steam turbine is obtained by the rate of change in momentum of a high velocity jet of steam impinging on a curved blade which is free to rotate. The steam from the boiler is expanded in a nozzle, resulting in the emission of a high velocity jet. The inlet angle of the reaction stages are the same as the nozzle angles of the. Comparing combined gas tubrinesteam turbine and marine. 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 method sufficiently accurate to. The steam coming from the boiler is fed to the first set of fixed blades i. Steam turbine basic parts mechanical engineering site. Therefore, for good efficiency the blade velocity should be about one. Steam expands from boiler pressure to the condenser in one stage.
These jets contain significant kinetic energy, which is converted into shaft rotation by the bucketlike shaped rotor. In all turbines the rotating blade velocity is proportional to the steam velocity passing over the blade. Pressure compounding is the method in which pressure in a steam turbine is made to drop in a number of stages rather than in a single nozzle. This highvelocity strikes the turbines rotor and the speed of the rotor becomes high. Type of compounding refers to the use of blading which causes a series of pressure drops, a series of velocity drops, or a combination of the two.
Reaction turbine this type of turbine the rotor blades act as nozzles. Steam turbines velocity compound has a few disadvantages which include high friction losses due to high steam velocity. There is a reduced amount of work performed in the lowpressure stages. Rocket turbine design emphasizes power density, because of the overriding concern for mass saving. Velocity kinetic energy of steam is converted to useful work in more than one stage. The nozzles are fitted to the casing and the blades are keyed to the turbine shaft.
Compounding of steam turbine turbine turbomachinery. In steam turbine compounding there are three major forms. Therefore, for good efficiency the blade velocity should be about one half of the steam velocity. Compounding of steam turbines in order for the steam to give up all its kinetic energy to the moving blades in an impulse turbine, it should leave the blades at zero absolute velocity. Rateau turbine pdf pressure compounding is the method in which pressure in a steam turbine is made to. Compounding is the splitting up, into two or more stages, of the steam pressure or velocity change through a turbine. Pressure compounding it is used to solve the issues of high blade velocity in the. Multiflow and compound arrangements shaft with one generator tandemcompound turbines or utilizing two shafts, each with its own generator cross. A multiple system of rotors are connected in series keyed to a common shaft and the steam pressure or velocity is absorbed in stages as it flows over the blades.
The compounding is the way of reducing the wheel or rotor speed of the turbine to optimum value. The thermal energy contained in the steam is converted to the mechanical energy by expansion through the turbine. It may be defined as the process of arranging the expansion of steam or the utilization of kinetic energy or both in several rings. The reaction principle, the impulse turbine, compounding of impulse turbine. Applications of steam turbines power generation transport 4. Pdf power plant lecture notes chapter2 steam power. The steam turbine is one kind of heat engine machine in which steams heat energy is converted to mechanical work.
It is the process by which rotor speed come to its desired value. There are several methods of reducing the speed of rotor to lower value. This condition will exist if the blade velocity is equal to one half of the steam velocity. Each stage consists of rings of fixed and moving blades. The technical specification of the tc4f40 1,000mw and 700mw steam. Division of steam flow indicates whether the steam flows in just one direction or if it flows in more than one direction. Steam turbine interview questions are you a person with a degree in mechanical or technical engineering.
There is no piston rod,flywheel or slide valves attached to the turbine. A compound turbine is a steam turbine in which there are two casings, a highpressure casing and a lowpressure casing, operating in concert to extract work from a single source of steam. So, steams pressure drop and it will increase its velocity. Unit iii unit iii steam nozzles and turbines flow of steam through nozzles, shapes of nozzles, effect of friction, critical pressure ratio,supersaturated flow. Introduction of steam turbine,part1,unit2,turbo duration. Impulse turbine efficiency calculation methods with. The turbine blades are made up of chromiumnickel steel or 17 cr ni steel.
Difference between velocity compounding turbine and. Power plant lecture notes chapter2 steam power plant cycles. Compounding of steam turbine is used to reduce the rotor speed. Turbine classification in order to better understand turbine operation, five basic classifications are discussed.
In principle, the impulse steam turbine consists of a casing containing stationary steam nozzles and a rotor with moving or rotating buckets. Cross compound steam turbine arrangement for marine use. There are two types of modern steam turbines impulse turbine in this type of turbine the steam nozzles direct superheated steam at the buckets of rotor blades, the impact of this causes the rotor to rotate. Impulse and reaction principles, compounding, velocity diagrams for simple and multistage turbines, speed regulationsgovernors and nozzle governors. Cross compound steam turbine arrangement compounding is the splitting up, into two or more stages, of the steam pressure or velocity change through a turbine. The method in which energy from steam is extracted in more than single stage is called compounding. This type of compounding is known as the pressure compounding and the nozzle and blade arrangement for a pressure compounded impulse turbine is sketched. The typical main turbine in nuclear power plants, in which steam expands from pressures about 6 mpa to pressures about 0.
Impulse turbines, reaction turbines, the impulse principle, the reaction principle, the impulse turbine, compounding of. This method of compounding is used in rateau and zoelly turbines. Lecture series on steam and gas power systems by prof. In modern steam engine practice high pressure steam is used, as the use of such a. In fact, a series of velocitycompounded impulse stages is called a. Efficiency, while clearly a consideration, takes a less prominent role than in aircraft turbine design. What is velocity and pressure compounding in impulse turbine. 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. This highvelocity strikes the turbines rotor and the speed. With over eighty years of experience we support and assist our customers with advanced engineering, production and quality expertise. Nozzles are used to guide the steam to hit the moving blades and to convert the pressure energy into the kinetic energy. Pressurevelocity compounding curtis turbine curtis turbine pressurevelocity compounding. Two types of modern steam turbines and their mechanical.
This tends to favor low reaction turbines and when multistaging, velocity compounding over pressure compounding. Normally the high pressure and intermediate pressure stages of a steam turbine are of the impulse type. Also, it is hard to design and fabricate blades which can tolerate such high velocities. In the case of small impulse turbine, the nozzles are located in the lower half of the casing. The nozzle angles for the first two impulse turbines are the same. A compound engine is an engine that has more than one stage for recovering energy from the same working fluid, with the exhaust from the first stage passing through the second stage, and in some cases then on to another subsequent stage or even stages. Thermal engineering pdf of rk rajput for mechanical. The steam is partially expanded in the highpressure casing, then exhausted to. In this type of compounding the steam is expanded in a number of stages, instead of just one nozzle in the velocity compounding. Also, if you observe, the moving buckets in impulse turbine are designed to get pushed by the steam. A turbine was investigated by various methods of calculating its efficiency. Compounding of steam turbine mechanics rotating machines. In this system the steam turbine cycle is fed with the steam produced in the waste heat boiler supplied with the exhaust gas from the gas turbines.
Impulse turbine and reaction turbineprinciple, working. In fact, a series of velocitycompounded impulse stages is called a pressurevelocity compounded turbine. In order for the steam to give up all its kinetic energy to the moving blades in an impulse turbine, it should leave the blades at zero absolute velocity. Through optimal application of technology and proven expertise, stork turbo blading is unmatched in. Impulse stages may be either pressurecompounded, velocitycompounded, or pressurevelocity compounded. Steam turbine working principle and types of steam turbine.
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