Figure 4 shows steam process in enthalpy against entropy diagram of curtis and single row rateau turbine. Unit iii unit iii steam nozzles and turbines flow of steam through nozzles, shapes of nozzles, effect of friction, critical pressure ratio,supersaturated flow. A steam turbine consists of a rotor resting on bearings and enclosed in a cylindrical casing. As the steam turbine system various its operation to satisfy the demand, steam pressure at various turbine locations change accordingly. Variable geometry has been employed in turbines operating with free power turbines to improve the off design thermal efficiency i. Steam turbines construction of nozzles and diaphragm. A steam turbine is a device driver that converts kinetic energy steam energy of movement to mechanical energy. Turbine casing drains remove the condensate from the turbine casing during warmup, securing, maneuvering and other low flow conditions. In an inner barrel design, the inlet nozzle passages, nozzle ring, and. The velocity triangle between nozzles stationary blades and buckets moving. The steam possessesa very high velocity at the end of the expansion, and the enthalpy decreases as.
They convert thermal energy in the steam to mechanical energy. Turbines may also incorporate variable geometry and this is usually applied to power turbines where the nozzle guide vanes ngvs are turned to alter the flow capacity and thus the turbine characteristic. The throttle valve assembly regulates the amount of steam entering the turbine. A convergingdiverging nozzle condi nozzle, or cdnozzle, is the only one to get supersonic flows with m 1 when chocked. Steam generator, turbine, pump, nozzle, throttling, the mathematical expression of the 1st law for a closed system, examples of closed. If the leaving kinetic energy fromtheexhaustiswasted,thentotaltostaticef. The main use of steam nozzle in steam turbines, is to produce ajet of steam with a high. In an inner barrel design, the inlet nozzle passages, nozzle ring, and one or more subsequent stages are contained in a second case. He is currently responsible for the design and development of special purpose steam turbines for the petroleum industry in accordance with api 612. In a turbine designed for partialarc admis sion, the firststage nozzles are divided into sep arate nozzle arcs typically four to eight, and each arc is connected. The flow of steam through nozzles may be takenas adiabatic expansion. Steam process in steam turbine steam entrance to turbine through governor valv e to control steam capacity and therefore to control turbine speed. The definition of an impulse turbine is that the majority of the fluid expansion takes place in the fixed turbine stators.
The modern steam turbine was invented in 1884 by charles parsons, whose first model was connected to a dynamo that generated 7. Steam turbine design options, how to specify or upgrade 31 figure 4. Engineer of the turbine design section at mitsubishi heavy industries, ltd. Steam turbines classification, governing equations and. In principle, the impulse steam turbine consists of a casing containing stationary steam nozzles and a rotor with moving or rotating buckets.
Thus a steam turbine could be viewed as a complex series of windmilllike arrangements, all assembled on the same shaft. The desired combination of high power output and compact design makes the impulse turbine a favorable choice, compared to the reaction turbine which may offer a higher efficiency, at the cost of a larger design. Consider a unit mass flow of steam through a nozzle. Impulse turbine efficiency calculation methods with organic. This usually means protecting the steam turbine from overspeeds, water induction, loss of lube oil, corrosive steam, and sticking valves that could cause major damage to the turbine, and conducting internal inspections of the turbine. When the steam passes through the stationary nozzles and is directed at high velocity against the rotor buckets. Speed control systems for steam turbines consist of three basic elements. Understanding and preventing steam turbine overspeeds 1 control design intentions is very important. Pdf power plant lecture notes chapter4 steam turbine. Since then turbines based on these principles have evolved in parallel and in fact merged to some degree. Pdf design and analysis of steam turbine blades researchgate.
Output power, speed and enthalpy range for several design of curtis turbine. Dry saturated steam is expanded in a nozzle from 1. Article pdf available in journal of power and energy engineering. Maintenance and overhaul of steam turbines wgp42 05. The optimum value of the nozzle outlet angle of turbine stages.
Despite efforts to develop alternative energy converters, electricity from steam will continue, for many years, to provide the power that energizes the united states and world economies. Accurate stagebystage modelling of axial turbines using an. Principles of operation of a steam turbinewhen high temperature steam passes through a steam turbine. Impulse turbine impulse steam turbine stage consists as usual from stator which known as the nozzle and rotor or moving blades impulse turbine are characterized by the that most or all enthalpy and hence pressure drop occurs in the nozzle. Calculate base dimensions of the nozzle and state of water steam at the exit.
Schofield ge company schenectady, ny introduction the need to provide stateoftheart products for a diverse and everchanging market is the chal lenge facing steam turbinegenerator manufactur ers in the 90s. The design goal of a dense pack retrofit is to put the most efficient steam path into an existsteam turbine uprates ge power systems ger4199 2. Recruitment and assessment centre, defence research and development organisation, lucknow road, timarpur, new delhi 110 054, india. 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. Delivering cuttingedge turbine and generator technologies. Following figures show steam process in steam turbine. This is caused by a region of increasing pressure toward the stagnation point of a blade or strut. First, a brief introduction of ffpp fundamentals and con. Recent trends in repair and refurbishing of steam turbine. Pdf design of steam turbine for electric power production using.
Another complication in the design of steam through a nozzle is due to a phenomenon known as supersaturation. Flow of steam through nozzles, shapes of nozzles, effect of friction, critical. This article provides an overview of fossilfuel power plant ffpp con. The mass flow rate of water steam must be 0,3 kgs1. To supply high velocity jet of steam in steam turbine.
In a typical turbine, steam flows in at a speed near 100 miles per hour and at. The actual heat drop h 1 h3 is known as useful heat drop. Thermal engineering pdf of rk rajput for mechanical. Recent trends in repair and refurbishing of steam turbine components a k bhaduri, s k albert,skrayandprodrigueza indira gandhi centre for atomic research, kalpakkam 603102, india apresent address. The primary operating principle of a turbine is to convert steam energy into mechanical energy that can be used to drive rotating equipment. Designation quantity note and additional information 1 2 turbine type, figure 3 rateau stages 3 condensing turbine 4 required condition 5 6 driven equipment syngas compressor 7p kw5780 8 n rpm 10200 9 pi bar a 40 10 ti c 400 11 po bar a 0. Sensing elements include fly ball weights, electric generators, and positive displacement pumps. In this respect, the behavior of convergent and convergentdivergent nozzles is different. The invention of parsons steam turbine made cheap and plentiful electricity possible and revolutionized marine transport and naval warfare. He has more than 15 years of industrial experience. Steam enters a group of nozzles of a steam turbine at 12 bar and 2200 c and leaves at 1. Steam turbine two types of steam turbines were considered with an fem analysis, those being back pressure type and condensing type.
This video will explain the inner workings of the steam turbines and why they. Rotor means which part rotate and stator means which part is fixed. Design parameters steam turbine mechanical engineering. Ger3705 ge steam turbine design philosophy and technology. The steam turbine is a prime mover that converts kinetic energy in steam into rotational mechanical energy through the impact or reaction of the steam against the blades. In general, a steam turbine is a rotary heat engine that converts thermal energy contained in the steam to mechanical energy or to electrical energy. Steam turbine calculation sheet design and selection. After passing through the throttle valve, steam enters the nozzle block. Aug 19, 20 a condenser installed at the exhaust or low pressure end of the turbine receives and condenses the steam prior to it being pumped back to the boiler. Design of steam turbine for electric power production using. Mar 31, 2017 steam turbines lie at the heart of these power plants. An entire 180 segment can be lowered into position because an inner arcuate portion 58 of the nozzle block fits over and captures mating portions of the casing rather than. Understanding and preventing steam turbine overspeeds by. It was applied to a number of turbines, and produced excellent offdesign results.
Supersonic flow in cdnozzles presents a rich behaviour, with shock waves and expansion. In reaction turbine, there is no nozzle to convert steam energy to mechanical energy. For example, nozzlewake interactions and structural features interfere with. This turbine is a velocity compounded curtis stage having a pressure ratio of 221 and a design mach number from the nozzles of 2. Impulse and reaction principles, compounding, velocity diagrams for simple and multistage turbines, speed regulationsgovernors and nozzle governors. Steam turbines are one of the most versatile and oldest prime mover technologies still in general production used to drive a generator or mechanical machinery. The design goal of a dense pack retrofit is to put the most efficient steam path into an exist steam turbine uprates ge power systems ger4199 2.
Pdf on aug 1, 2019, mingyu zhu and others published design and analysis. There is only one value of the ratio p2p1, which produces maximum discharge from the nozzle. The design limits, operational experience, and rugged dependability synonymous with ge turbine design is not changed with a dense pack. In turbines there are basically 2 part one is called rotor and another is known as stator. What is steam turbine description and characteristics. A nozzle is, normally, designed for maximum discharge by designing a. Development of titanium 3600rpm50inch and 3000rpm60inch. Classical nozzle theory is applied to model the rotor and stator of a turbine stage. A dropin nozzle block 40 formed in two 180 segments 52 that can be simply lowered into position within the nozzle chamber casing of a steam turbine 42. High pressure, high temperature steam expands in nozzles and comes out at a high velocity. Flow of steam through nozzles, shapes of nozzles, effect of friction, critical pressure.
The aim of this study is to design a steam turbine for a small scale steam power plant with target of producing electricity. The first steam turbine used for power generation was invented in 1884. Palm kernel shell, steam turbine, power plant, design software. Motivated by this obvious concern with improving efficiency, an inner barrel style steam end was one of the first options considered. Turbine stages, comprising nozzlestator and rotor blade rows. Assume friction loss in the nozzle is equal to 10% of the total enthalpy drop. In case of turbines with cooling water preheating and lowpressure lp bypass, prior to supplying steam the regeneration and dumping systems have to be. To inject feed water in to the boiler in a steam injector. Thus, the better the design of the blade, the more efficient the turbine will be. Steam power plant configuration, design, and control. Oct 15, 2016 nozzle is a duct by flowing through which the velocity of a fluid increases at the expense of pressure drop. Region of high turbulence between control stage and second stage.
A convergingdiverging nozzle condi nozzle, or cd nozzle, is the only one to get supersonic flows with m 1 when chocked. In its simplest form, a steam turbine consist of a boiler steam generator, turbine, condenser, feed pump and a variety of auxiliary devices. Steam consumption of steam turbine is depending to required output power and efficiency of. Mar 07, 2015 vanita thakkar bit 16 energy conversion in steam turbine energy conversion in steam turbine takes place in two steps. The design of nozzle should be such as to permit easy manufacturing and finishing and allow accurate channel sections to be obtained specially at the high pressure end of the turbine. Feb 02, 2015 the steam turbine generators used today produce approximately 85% of the electricity in the united states. This vacuum condition is different from a back pressure type.
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