There are two classical types of turbine stage designs. A steam turbine is a mechanical device that extracts thermal energy from pressurized steam and transforms it into mechanical work. Lathrop trotter is the source for gas and steam turbines, turbine generator sets, and combined heat and power solutions. Taking into consideration thermal expansion and dilatation measured from photogrammetry it is observed that the turbine generator gets misaligned when the steam turbine gets hot figure 6. The highpressure turbines are modelled for a design situation and for partload situations with 80% and 40% of the power at design situation. Thermal power plant based on a rankine cycle in a simple rankine cycle, steam is used as the working fluid, generated from saturated liquid water feedwater. Steam turbines startups 1 principles of steam turbines startups. Steam process in steam turbine steam entrance to turbine through governor valv e to control steam capacity and therefore to control turbine speed. About the presentation this presentation teaches the reader about the operation and importance of steam turbines in electricity generation. To maximize turbine efficiency the steam is expanded, doing work, in a number. The basic element in a turbine is a wheel or rotor with addles, propellers, blades, or buckets arranged on its circumference in. The gas turbine is a steady flow device in which air is compressed to a high pressure in the compressor, fuel is added in the combustion chamber, resulting in a high temperature at the turbine inlet. In some stations, lp turbine exhaust hood temperatures. Free kindle book and epub digitized and proofread by project gutenberg.
In noncondensing turbines or backpressure turbines, steam exhausts at a pressure greater than. The primary purpose of a differential expansion monitor is to guard against axial rub between rotating and stationary parts. Steam turbines classification, governing equations and. Modern ge steam turbines for electrical power generation are the result of. See more ideas about steam turbine, abandoned factory and industrial photography. Steam does not condense at the saturation temperature corresponding to the pressure. Arabelle uses more efficient single flow steam expansion. Impulse steam turbineimpulse steam turbine on impulse turbine a thermal expansion take place only in theon impulse turbine a thermal expansion take place only in the nozzles and static energy is converted to the kinetic energynozzles and static energy is converted to the kinetic energy there is no pressure different at inlet and outlet of. The remaining steam is then expanded through a low pressure turbine to 1.
The turbine consists of three casings, high, medium and low pressure. Ger3646d steam turbines for large power applications. Isentropic expansion expansion in a steam turbine steam from the boiler expands adiabatically from state 3 to state 4 in a steam turbine to produce work and then is discharged to the condenser partially condensed. Sensonics technical note ds1220 differential expansion measurements on large steam turbines one of the challenges facing instrumentation engineers in the power generation sector is the accurate measurement of shaft growth relative to casing on large steam turbines. Mathematical model for digital simulation of steam turbine set dynamics and online turbine load distribution institute of heat engineering, warsaw university of technology, nowowiejska 25, 00665 warsaw, poland abstract the general structure and purposes of. Steam conditions the turbine expansion line or condition curve represents steam conditions prevailing in sequential stages of the steam turbine. Figure 3 supersaturated expansion of steam into wet region 3. W501d gas turbine generator system currently used in a number of utilities. Steamturbine principles and practice by croft, terrell, 1880publication date 1923 topics steamturbines. Parsons main thrust for the steam turbine was for generating electrical power, but he also had his eyes on applying the steam turbine to drive ships of all kinds. Chaplin encyclopedia of life support systems eolss figure 4.
Page 522 end of chapter answer guide 2nd class b1 10. Dec 10, 2015 this turbine is called rmaple impulse turbine since the expansion of the steam takes place in one set of the nozzles. Steam turbines are used to drive the electric generators in modern power plants. 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. This measurement is typically performed on larger steam.
The utility gas turbines present a number of challenges as compared to conventional steam turbines. Consider steam turbine drives for rotating equipment steam turbines are well suited as prime movers for driving boiler feedwater pumps, forced or induceddraft fans, blowers, air compressors, and other rotating equipment. Plotted on a mollier diagram it provides a useful visual image of these conditions. Steam turbine generator shaft grounding principles historically, the problems and solutions to electrostatic and magnetically induced voltages on the steam turbine generator shafts of the test utilitys steam electric stations have been a continuous one.
Fluid dynamic investigation of an alternative extraction. During the design of a steam turbine, limiting dif ferential expansion is calculated relative to the thrust bearing position and clearance is then pro vided to assure. The pressurized steam is expanded to lower pressure in a turbine, then exhausted either to a condenser at vacuum conditions, or into an intermediate temperature. Turbine supervisory instrumentation system tsi on large steam turbine generator applications.
Prior to supplying steam to the turbine, the steam supply pipelines have to be drained and heated up. Isentropic expansion within a steam turbine system. The steam turbine is a form of heat engine that derives much of its improvement in thermodynamic efficiency through the use of multiple stages in the expansion of the steam, which results in a closer approach to the ideal reversible process. Approach to high efficiency diesel and gas engines pdf.
Steam turbine casing front side is generally free and slide on the front side bearing pedestal. Process of complete expansion of steam takes place in stationary nozzle and the velocity energy is. The steam does work on the surroundings blades of the turbine and loses an amount of enthalpy equal to the work that. Steam leaves the fixed blades of one stage of a reaction turbine at 122 ms with an exit angle of 23. In a steam turbine, highpressure steam from the boiler expands in a set of stationary blades or vanes or nozzles. Generally in a steam turbine the rear support of the steam turbine or the rear side of the casing is fixed. To fix the extraction pressure level, it is necessary to control the low pressure turbine downstream of the steam extraction point. Nevertheless modern steam turbines are very efficient and operate with internal efficiencies within the range of 80 percent to 90 percent depending upon the steam conditions. The current w501d model represents a power enhancement over the earlier westinghouse 70 mw units which have been in service for many years. This turbine is called rmaple impulse turbine since the expansion of the steam takes place in one set of the nozzles. A steam turbine undergoes thermal expansion as its case heats during steam admission. We work to assess and address specific application needs so we can specify and develop a turbine system package that meets and exceeds goals.
It includes heat exchange and energy conversion equipment. High pressure steam is admitted slowly into a turbine to warm it up and remove condensate moisture produced by condensation. What is differential casing expansion in steam turbine. Because the turbine generates rotary motion, it is particularly suited to driving electrical generators about 90% of all electricity generation in the united states 1996 is by use of steam turbines 1 wiser. Consider steam turbine drives for rotating equipment.
To fix the extraction pressure level, it is necessary to control the low pressure turbine downstream of. All steam entering the feed pumps shall be a saturated fluid. Velocity diagram of simple impulse turbine, various performance parameters. Although the application of differential expansion and rotor expansion have much in common, it is important to understand the difference between the two measurements. In its simplest form, a steam turbine consist of a boiler steam generator, turbine, condenser, feed pump and a variety of auxiliary devices. Turbines in ohio, kentucky and indiana lathrop trotter. Steam from the boiler is expanded in the nozzle blade passages to produce high. Hp part consists of two horizontally split casingsinner is placed inside, outer casing with scope for expansion in all direction. This saturated steam flows through the turbine, where its internal energy is converted into mechanical work to run an electricity. Isentropic expansion within a steam turbine system physics. Both the ends are supported on independent pedestals.
Figure 4 shows steam process in enthalpy against entropy diagram of curtis and single row rateau turbine. Following figures show steam process in steam turbine. W501d gas turbinegenerator system currently used in a number of utilities. Research paper on study of steam turbine amanraj dronacharya college of engineering, gurgaon123506, india abstract. In the second part of this series, the author talked about the story of the first little toy turbine. Dec 19, 2014 velocity diagram of simple impulse turbine, various performance parameters. In case of turbines with cooling water preheating and lowpressure lp bypass, prior to supplying steam the regeneration and dumping systems have to be.
Mathematical model for digital simulation of steam turbine. Differential expansion on a turbine is the relative. As the steam flows through the nozzle its prenzsure fall. Rotor expansion on a turbine is the absolute measurement of the rotors axial thermal growth with respect to the turbine s foundation.
High velocity steam hits the moving blades converting the kinetic energy into mechanical work. Each time it starts, the turbine after rolling about 2 or 3 hours differential expansion reach to its limit 1mm, and turbine trips, we have scyncronizing and reaching to 20mw during this 3 houres. Turbine stages, comprising nozzlestator and rotor blade rows. The results of the numerical simulations the computation has been done by using the method of characteristics and method of finite differences. Reaction turbine blading and conditions figure 3 shows, at the top. When turbine is in service, superheated steam temperature above 540 degree celsius is admitted into the turbine. This service generally calls for a backpressure noncondensing steam turbine. As seen in figure 5, the turbine generator was aligned in cold condition. Unlike with reciprocating engines, for instance, compression, heating and expansion are continuous and. What links here related changes upload file special pages permanent link. Steam turbine fundamentals an introductory guide to the operation of modern steam turbines v. Differential expansion of the steam turbine cr4 discussion.
A typical large steam turbine power generation unit will have a thick case, on the order of 12 to 18. 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. Two casing, doubleflow steam turbine with shellmounted valves. The first steam turbine used for power generation was invented in 1884. 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. A multistage steam turbine is considered to be one of the worlds most powerful engines.
The computeraided design cad files and all associated content posted to this website are created, uploaded, managed and owned by third party users. Differential expansion monitoring measures the change in axial clearances between the machine rotor and casing caused by thermal changes inherent in most machines. Differential expansion sensitivity studies during steam. Extraction steam turbines are frequently used in cogeneration as well as industrial power plants. Thermalengineeringbyrkrajput chapter19 steam turbine. Jun 24, 2015 in the second part of this series, the author talked about the story of the first little toy turbine. Sensonics technical note ds1220 differential expansion. Pdf power plant lecture notes chapter4 steam turbine.
A steam turbine is a device that extracts thermal energy from pressurized steam and uses it to. We are commissioning this turbine for the first time. The expansion process provides significantly more power than is. Dynamic analysis and field balancing of 100 mw utility gas. Rotor expansion on a turbine is the absolute measurement of the rotors axial thermal growth with respect to the turbines foundation.
As aminimum, these are the hp and lp turbine inlet steam and metal temperatures. Notes references module 2348 the turbine supervisory system. Elec0047 power system dynamics, control and stability. Each cad and any associated text, image or data is in no way sponsored by or affiliated with any company, organization or realworld item, product, or good it may purport to portray.
Nonlinear mathematical model of the condensing steam turbine 875 where. This provides a follow up of basic engineering cycles with applications to conventional power plants. This article focuses on marine steam turbines and their applications. 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. The extremely large casing sizes and extremely high steam temperatures of turbines used in electric power generation service can easily result in up to two inches 50 mm of axial growth. Likewise, it undergoes contraction as its case cools during steam reduction. Earlier steam turbine generating units had an inherent grounding. An analysis of a thermal power plant working on a rankine.