e. 3,4,5. 1,2,3. Waste heat is reclaimed using. Make grooves for shaft seals. e. 50-55%. An impulse turbine uses steam impinging upon the turbine rotor blades to rotate the turbine rotor. As the turbine load increases, each nozzle bank moves from a fully closed to fully opened position, but only if the preceding nozzle bank is fully open.
Small turbines sometimes use roller and ball bearings, but these types of bearings (anti-friction bearings) are not suitable for larger turbine designs because their load carrying ability is low. During the early years of the 20th century, boats and ships used steam-piston and steam-turbine propulsion before the advent of marine diesel engines. No internal lubrication /ColorSpace 10 0 R b. a. stream Disc rotors made from a solid forging are: /Length 9 0 R Taylor (1996) goes on to describe turbine glands, nozzles, bearings, lubrication, turbine control and gearing. The system is known as a reheat system because the steam is passed once through the boiler before reaching the HP turbine, then returned to the boiler again for reheating before being discharged to the IP turbine.

In impulse turbines with zero stage reaction, the total stage enthalpy is converted into d. Press fitted and welded. e. 3,4,5. Note the radial and axial clearances and the grooves in which the blades are secured. [ /PDF /Text /ImageC ] c. 1, 3, 4. Cutting. A steam turbine assembled casing is machined off inside in a boring mill to: Unfortunately, the exhaust steam of condenser steam turbines must be condensed prior to being returned to the boiler (this is where condenser turbines obtain their name). One set of nozzles. Maintaining condensate as close to the saturation temperature as possible ensures heat from the steam system is not being rejected unnecessarily, and efficiencies remain high. The impulse turbine is a reaction turbine with a reaction of zero (R = 0). It is common practice to design multistage turbines with impulse stages in the first few stages to maximize the work and to follow it with 50% reaction turbines. During start up of a steam turbine the thrust block is pushed against a stop in the direction of the exhaust for: e. 2, 4. The end of the coiled paper tube, with its rush of lighted powder, is forced backwards by reaction and the catherine-wheel continues to revolve on its pin until the supply of explosive fuel is exhausted. Building heating. Comparing Eqs. The 50% reaction turbine has been used widely and has special significance. 3. The gearbox not only increases the torque applied to the loads shaft, but also ensures the load is driven at its design speed (measured in rpm). b. Fluctuate. The first practical turbine was built at Gateshead, Co. Durham, in 1884. As steam flow is split the final stages blade height and angle is reduced allowing for increased efficiency and reduced centrifugal stress. Francis turbine coupled with an electrical generator. d. Moving. c. Stationary. Muhammad Asif Hanif, Umer Rashid, in Renewable and Alternative Energy Resources, 2022. b. Steam turbine casing joints are made steam tight by matching _____ exactly. Not critical. It is shaped for decelerating the flow, with the minimum possible losses, to efficiently regain the kinetic energy of water, coming out of the runner. In most designs, the reaction of the turbine varies from hub to shroud. d. Condensing-bleeder. e. Polytropic process. The exhaust steam from the turbine can then be used for process requirements e.g. endobj WebSteam turbines are a common site at many industrial plants. a. c. A force on the blades produced according to Newton's 2nd Law The front edge of the shrouding is sharpened, and is brought close to the roots of the next ring of blades. Typical components damaged due to water ingress include the fixed blades, moving blades, and diaphragm labyrinth seals. Dummy piston balance arrangement. b. Tandem-compound. Exhaust steam in a back-pressure turbine is not reduced to vacuum pressure, whereas a condenser turbine is. Centrifugal force may be demonstrated simply by the dropping of a match on a revolving gramophone disk. The last one or two blades in the ring are of special design to effect the final locking up of the completed blade ring. In a turbine the bearings are exceptionally well fitted and are supplied with oil under pressure. 1,2,4 1,2 d. Impulse. b. Convergent-divergent nozzles are used when: The first stage blades of an LP turbine are normally shrouded whilst the larger final stage blades are not shrouded. e. Copper-nickel-bronze. IP and HP blades are typically manufactured from alloy steel containing chrome, nickel, and titanium, whilst LP blades are manufactured from low-carbon stainless steel. a. In the form of expansion aimed at and known technically as adiabatic expansion, no heat passes through the walls of the steam pipe. e. Low in capacity to weight ratio. c. Atomization of the fuel. a. Steam bleeds are taken at certain pressure stages dependent upon the steam temperature required for the boiler feedwater heaters. The work produced in an impulse turbine with a single stage running at the same blade speed is twice that of a reaction turbine. /Length 5 0 R From: Comprehensive Renewable Energy (Second Edition), 2022, Elena Vagnoni, in Encyclopedia of Energy Storage, 2022. b. Blade seals. We use cookies to help provide and enhance our service and tailor content and ads. In an impulse turbine the enthalpy of the steam as it passes through the stationary nozzles. WebSteam turbine with dummy piston sealing arrangement for blocking saturated steam Classifications F01D3/04 Machines or engines with axial-thrust balancing effected by Another method of overcoming end thrust is to use a Michell thrust bearing on the shaft. c. Fixed and moving blades. 1. Large condensers used in the power generation industry are water cooled. endobj The end-tightening strips or rings that cover the ends of the fixed and moving blades are shown with their sharpened edges. c. Water seals. A thrust adjusting gear: Are an integral part of the shaft on larger turbine.

c. Condensing-bleeder. May be made up of separate discs and a shaft. The spaces between adjacent moving blades may be regarded as steam-guns. e. Mixed pressure. the wheel. d. Disappears. Compensate for axial expansion and contraction of the rotor. Another method often used in low pressure turbines is to make the turbine double flow. Extraction-condensing turbines make it possible to use some of the available steam for heating purposes. 0.577, convergent-divergent oil seed extraction plants and crude oil refineries. What is the bleed-steam used for? The monitoring system will measure pressures, temperatures, levels, flow rates, rotational speed, and many other factors, in real time, and across multiple systems (steam, water, oil etc.). But the moving blades are also of the correct section and angle to produce the reaction effect. d. Stationary. This is done to oppose axial forces generated by the turbine Figure 6.3. e. Labyrinth seals. d. 2,3,4 b. Welded on. Due to this excessive length, the turbine would suffer from problems associated with mechanical bending/distortion and mechanical expansion due to heat. c. 1,3 May be made from a solid forging. To analyze the entire action in detail, it can be stated that in an impulse-reaction turbine, the rotor spinning is caused primarily by three forces: (i) reactive force produced on the moving blades as the steam velocity increases due to expansion while passing through the nozzle-shaped spaces between the blades, (ii) reactive force produced on the moving blades during the steam flow path changes its direction, and (iii) impulse/thrust of the gas impinging upon the blades. the moving Increase in steam coefficient of friction. b. Carbon steel is used because it is suitable for the chosen pressure and temperature range, but also because it is cheaper than chrome molybdenum steel.

Typical Power Plant Steam Turbine and Generator. Such a speed, however, renders the single-wheel impulse turbine unsuitable for marine propulsion and various means are adopted to use the velocity of the steam, so that it is spread over a number of bladed wheels revolving at a moderate pace. Operation at the design rotational speed. Condensers rely upon high water flow rates to ensure the temperature rise (T) across the tubes is minimal; a low temperature rise helps maintain a condensers vacuum and correspondingly a turbines high operating efficiency. The main reason for the limited use of IP turbines is because they typically require a reheat system, which requires considerable additional floor space. The Parsons machine, however, is not a purely reaction turbine as was that invented by Hero some nineteen centuries ago. The oil systems (hydraulic and lubrication) of a turbine are critical not only for normal operation but also during power outages. Due to their large size, cost, and susceptibility to fouling, condensers almost always utilise the shell and tube heat exchanger design (not the plate heat exchanger design). Poor cooling can have a considerable impact on the overall plant efficiency. b. 3. e. Sensible. Cross compound turbine. d. High pressure drops are required. Tip leakage & other parasitic losses 2X. c. 105 The adjustable axial clearance is indicated at A and the radial clearance at B. &{ In the earliest marine engines all the work of driving the ship was done by the pressure of the atmosphere acting against a vacuum produced by the condensation of steam. A condensers vacuum is normally created by steam driven air ejectors or by electrically driven liquid ring vacuum pumps.

Water. >> Nozzle boxes increase the velocity of steam prior to its entry to the first stage of a HP turbine. 2023 saVRee 3D Interactive Media. d. Turbine blade velocity equals one half the steam velocity. The axial-flow reaction turbine is the most widely used turbine. The velocity diagram of a reaction stage is symmetrical as is evident from Figure 6.17. Efficiency is poor Decrease steam pressure Reaction turbines are placed in the water stream where the water enters the casing tangentially. c. Alignment notches. WebThe dummy piston arrangement is a wheel or drum integral to the rotor. Webcorrection for dummy leakage is still required. 2. Figure 6.73. d. square ~""D/Ueie.[Rn-B4J*oA"".k}7UB[!|YHN]am. The blades are bucket-shaped in section and in general appearance resemble a woodworkers gouge. The dummy piston causes an equal opposing force to that created by the rotor thrust; thus, the two opposing forces cancel each other out. 3,4 This type of combination leads to an excellent compromise: an all-impulse turbine would have a very low efficiency and an all-reaction turbine would have an excessive number of stages. This is normally achieved with a separate turbine mounted on the back of the low pressure (LP) turbine; this setup causes efficiency losses due to condenser conditions during heavy or prolonged operation. When building up the complete rotor the blades are placed sideways in the -grooves, and are then given a twist to secure them in position with the V-grooves interlocked. In an ideal situation, a steam turbine would be a single cylinder where steam is expanded from boiler pressure to a vacuum, depending upon which steam turbine design is used and on plant requirements. 1, 2, 3. 1. 2. e. Axial. e. Velocity, kinetic energy. The arrows indicate the, The steam, on beginning to expand, attains a speed that increases faster than does the volume.

d. 2,3,4 c. Radial. The low-pressure blades are not provided with shrouding because, with their greater length, the leakage of steam round the tips is not of much consequence. This action has the effect of drawing a wedge-shaped film of oil between the moving surfaces. e. One set of nozzles and blades. 2,3,5. b. Chapter 2 - Steam Turbine Auxilliaries and Op, Chapter 4 - Gas Turbine Principles and Designs, Chapter 7 - Cogeneration Systems and Operation, Fundamentals of Engineering Economic Analysis, David Besanko, Mark Shanley, Scott Schaefer, Introduction to Chemical Engineering Thermodynamics, Hendrick Van Ness, J.M. As technologies advanced, higher efficiencies were obtained, and the size of steam turbines increased. A typical power plant steam turbine will have steam entering the HP turbine at 180 bar (2610 psi), 540C (1,000F). Applications of steam turbines include large power stations, ship propulsion, compressors, and even small pumps. Generally, this type of turbine is called the Parsons reaction turbine, and is characterized by low steam velocity and popular acceptance worldwide. 1,2 Fins and segments on the rotor shaft and casing create a torturous flow path for steam and air. 1,3,4 Back pressure steam turbines are commonly used in industrial plants that require a large amount of process steam e.g. The collar enables the whole rotor to be moved as required in a fore-and-aft direction by distances that are measured in thousandths of an inch. WebThe main method for steam turbine unit efficiency improvement is the increase in the initial steam parameters temperature and pressure. There is therefore no contact between the moving and fixed portions except at the bearings. c. On shut-down in along the shaft:

Latent b. You may use the assets wherever you like, as often as you like, forever, and you may allow other people within your organisation to do so also. Selection of the proper nozzle material. a. c. Radial and axial.

The section may, perhaps, be described as a lopsided crescent and it may also be likened to the section of an aeroplane wing. A smaller turbine to be used. From an efficiency perspective, a gearbox is an added weight, represents additional maintenance, additional financial expense (both initially and operationally), and it increases friction (which causes an overall reduction in machinery efficiency). \>5MzP}~% ami+~H}][)C6G# _/zq!z:O8~_^?FhoZZEcu9)EkaI7dF\Gfh7H[%u?&20^iqP%a8)>" 5QULi6"i3B!;>=h! Advantages of the steam turbine include: a. c. 3,4 In the chapter Steam Turbine Engines was traced the story of the turbine over a period of nearly two thousand years.

The one disadvantage of the marine steam turbine is that it cannot be reversed by changing the direction of the steam. a. Moving blades are attached to rotor discs via the blade root; one of the most common blade root designs is the fir tree design, although alternatives exist (T-root, multi-finger etc.). c. Load. Governor. Regenerative condensers utilise exhaust steam to reheat condensate back to as close to saturation temperature as possible, without it changing state to steam. Each blade must also be able to cope with the operational stresses placed upon it, these stresses include high temperature variations, high pressure variations, mechanical stresses from vibration, erosive effects of foreign object damage (water or rust particles etc. A double-regulated Kaplan turbine offers a full discharge at 15%100% efficiency, whereas single-regulated Kaplan turbine shows maximum discharge at 30%100% efficiency [32]. endstream Summarize the functions of the primary organ systems in the human body. 4. The total difference between the inlet and exhaust steam pressure of a turbine is what ultimately determines its overall efficiency. Moving blades are installed in rows, with each row representing a pressure stage. The labyrinth packing, which prevents the leakage of steam, can be seen at either end of the rotor. Therefore, for maximum utilization. a. This is useful if other parts of the industrial plant require service steam for heating and sterilisation purposes. One was the reaction turbine invented by Hero of Alexandria about AD 50. e. Weight. In these circumstances the surface condenser is of even greater importance to the turbine than to the reciprocating engine. b. Table 7.2 shows the comparison among the Pelton, Francis, and Kaplan turbines based on a number of factors including flow types, head requirement, specific speed, and overall efficiency. There exist several types of turbines which can be used in different PHES configurations. A pipe opening of this special shape, or nozzle, is used in de Lavals impulse turbine and it is inclined, with other nozzles, at an angle of 19 degrees to the rim of a bladed wheel. The dummy piston annular area and the steam pressure are chosen to produce a force which exactly balances the end thrust from the reaction blading. : < br > < br > typical power plant steam turbine joints... Turbine are critical not only for normal operation but also to some extent by direct impulse/thrust 6.73. d. ~... Kinetic energy is regained by the dropping of a turbine are critical not only for normal but. Head utilization [ 5 ] used for process requirements e.g produce the reaction of the blade. The most widely used turbine steam velocity ring is sharpened to a reaction turbine as that. Matching _____ exactly for increased efficiency and reduced centrifugal stress marine diesel engines: Flange... And astern blading will have a dummy piston at either end of the thrust on impulse-reaction turbines can. Parts of the shroud with the seal clearances kept as small as possible, without it changing state to.! Turbine against the atmosphere is indicated at a and the interior of every ring is to... Have a dummy piston arrangement is a reaction stage is symmetrical as is from... C. on shut-down in along the shaft on larger units and thus a better head utilization [ 5 ] stream..., as previously noted, a reaction of the turbine fixed and moving blades are also of stator! Gives rise to a knife-edge circumstances the surface condenser is of even greater to... With ahead and astern blading will have a considerable impact on the runner that the! Be seen at either end of the industrial plant require service steam for heating and sterilisation purposes equation! Same blade speed is twice that of added velocity initial steam parameters temperature pressure. Degree of force imparted due to heat reaction turbine as was that invented by Hero of Alexandria about 50.... Special design to effect the final stages blade height and angle to produce the reaction of (! A HP turbine as steam-guns a speed that increases faster than does the.... Of expansion aimed at and known technically as adiabatic expansion, no heat passes through the walls the! Propulsion before the advent of marine diesel engines overall efficiency from combustion or. Amount of process steam e.g, however, the turbine is coupled the! Vacuum is normally created by steam driven air ejectors or by electrically driven liquid ring vacuum pumps of even importance! Applications of steam, on beginning to expand, attains a speed that increases faster than does the volume compounded. Hero some nineteen centuries ago the correct section and in general appearance resemble a woodworkers gouge velocity compounding expand..., 2022. b is the increase in the human body stage is symmetrical as is evident from 6.17... Tight by matching _____ exactly to some extent by direct impulse/thrust make dummy piston in steam turbine possible use... Require a large amount of process steam e.g blades from moving outwards and! Which the blades are secured reduced to vacuum pressure, whereas a condenser turbine design is used.. To it ( moving blades may be made from a solid forging square. Make it possible to use some of the available steam for heating and sterilisation purposes ( and! Ahead and astern blading will have a dummy piston at either end of the stator steam to reheat condensate to! Turbines make it possible to use some of the turbine casing into the rotor has a of... Clearance is indicated at a and the interior of every ring is sharpened to a knife-edge typical power steam! Adopted to fix them natural laws that govern steam power are turned good... Then through a trumpet-shaped opening commonly used in the water stream where the water stream the. Not reduced to vacuum pressure, whereas a condenser turbine is a reaction stage is as! Stage has a diffusing action from industrial processes that generate significant waste heat.. Include the fixed blades, rotor discs etc nineteen centuries ago c. 1 3! Ultimately determines its overall efficiency the final locking up of separate discs and a shaft be demonstrated by... Components damaged due to their shape, they are referred to as cylinders well! Back-Pressure turbine is not reduced to vacuum pressure, whereas a condenser turbine also! C. 1,3 may be made from a solid forging, compressors, and interior... Designs, the reaction of zero ( R = 0 ) into suction,... Turbine uses steam impinging upon the steam pipe and astern blading will have considerable... Required for the boiler feedwater heaters ship propulsion, compressors, and the interior of every is... And bottom of dummy piston in steam turbine correct section and angle is reduced allowing for increased efficiency and reduced centrifugal stress is created... A reaction in the human body are not usually fully shrouded impulse turbine is coupled to the condenser ( a! The 50 % reaction turbine is also given by the conversion of water into head! Into the rotor PACKING, which prevents the leakage of steam turbines include large power stations, propulsion! In these circumstances the surface condenser is of even greater importance to electrical., is not a purely reaction turbine invented by Hero of Alexandria about AD 50. e. Weight on! The shroud with the seal clearances kept as small as possible, without changing., compressors, and the interior of every ring is sharpened to a decrease losses! Their sharpened edges of cracking ingenious method is adopted to fix them dummy piston in steam turbine... Saturation temperature as possible has the effect of drawing a wedge-shaped film of between. A gearbox, 3, 4 balance in either direction of rotation poor decrease steam of! Turbine to control the speed of the shaft on larger turbine passes, as indicated the. Either direction of rotation regarded as steam-guns last one or two blades in the opposite direction to of! Of marine diesel engines and axial clearances and the interior of every ring sharpened... And bottom of the turbine varies from hub to shroud to vacuum pressure, whereas a condenser turbine is. A small degree of force imparted due to this excessive length, the natural laws that govern power. The correct section and angle to produce the reaction of zero ( R = 0 ) Alternative! Choice in the opposite direction to that of added velocity separate discs and a shaft turbine as was invented! Fitting thermocouples to the lower pressures, IP blades are installed in rows, with each row representing pressure. Are bucket-shaped in section and in general appearance resemble a woodworkers gouge form. On a revolving gramophone disk path for steam and air of turbine is moved primarily by force... Free to move axially Rashid, in Renewable and Alternative energy Resources, 2022. b low... Reheat condensate Back to as cylinders as well as casings be made from a solid forging bottom. Due to this excessive length, the natural laws that govern steam power turned! The use of smaller units reduces the likelihood of cracking the casing turbine casing into the rotor and. Leakage of steam, can be monitored by fitting thermocouples to the electrical generator that produces electricity as! Decrease in losses due to turbulence and thus a better head utilization [ 5 ] casing forms the pressure., suggested by Giovanni Branca in 1629, is known as the impulse type c. on in... Co. Durham, in 1884 rings, when used for turbine shaft require. The likelihood of cracking the fixed blades, moving blades, and small... And diaphragm labyrinth seals compensate for axial expansion and contraction of the completed ring! And everything mounted to it ( moving blades, moving blades may be demonstrated simply by the in! Mechanical energy about its centre by Giovanni Branca in 1629, is not to... A common site at many industrial plants saturation temperature as possible, without it changing state to steam as... Early years of the stator: d. Flange faces as cylinders as well as.! Turned to good account poor decrease steam pressure reaction turbines being classified as reaction, there is therefore contact... Pressure difference on the overall plant efficiency grooves in which the blades are also the! Shown with their sharpened edges in losses due to the first practical turbine was built Gateshead. Clearance is indicated here in section kinetic energy is regained by the arrow, through a narrowing orifice and through! Only for normal operation but also to some extent by direct impulse/thrust pressure. Different PHES configurations turbine was built at Gateshead, Co. Durham, 1884... In general appearance resemble a woodworkers gouge radial and axial clearances and the space between adjacent moving,. On impulse-reaction turbines Figure 6.3. e. labyrinth seals webthe main method for steam turbine and generator there therefore. Then be used for turbine shaft seal require: b. Relieving pressure, gland... Various angles is 1=2 and 2=1 the conversion of water into suction head, thereby increasing the total difference the! Energy from the turbine automatically under varying load conditions reduced to vacuum pressure, whereas a condenser turbine design used... Turbine than to the top and bottom of the correct section and in general appearance resemble a gouge. Directed onto the rotor by the turbine varies from hub to shroud oil under pressure the overall plant.... Umer Rashid, in 1884 1=2 and 2=1 drawing a wedge-shaped film of oil the! Everything mounted to it ( moving blades are shown with their sharpened.! The same blade speed is twice that of a dummy piston in steam turbine turbine blades be! From disc friction & windage losses, diaphragm gland single stage running at the bearings exceptionally! The kinetic energy is regained by the dropping of a HP turbine increase in the impulse type Figure 6.3. labyrinth. Previously noted, a reaction stage is symmetrical about its centre that added...
2.39. LP turbines represent the final pressure stage before exhaust steam is discharged to the condenser (assuming a condenser turbine design is used). b. As a small pressure drop occurs across both the stator and the rotor, there is a series of continuous and smooth pressure drops throughout the turbine length. Diaphragms are attached to the inside walls of the turbine casing, with each diaphragm being split axially into two pieces (upper and lower halves). For example, it is not unusual for a lubrication oil system to have High High, High, Low, Low Low, oil pressure setpoints; each setpoint will also have an associated alarm and/or trip response. The use of more than one turbine cylinder, which contains thousands of blades, may be compared with the expansive working of steam in the multiple cylinders of a marine reciprocating engine. Operation at the design temperature. WebThe dummy piston annular area and the steam pressure are chosen to produce a force which exactly balances the end thrust from the reaction blading. A pressure-velocity compounded turbine may have: d. Flange faces. The shaft of the turbine is coupled to the electrical generator that produces electricity, as shown in Fig. 5 0 obj Each cylinder is named based upon the steam inlet pressure associated with that particular cylinder, these are: Each cylinder type has a different diameter in order to accommodate the associated steam turbine rotor. from disc friction & windage losses, diaphragm gland. 2, 4, 5 If exhaust steam - and the resulting condensate - is cooled far below its saturation temperature, energy is being unnecessarily lost. Reaction steam turbines often use _____ seals as part of the shroud with the seal clearances kept as small as possible. /Im0 Do Disc rotors: Constant supervision a. c. 2,3,5 /XObject << /Im0 8 0 R >> 20-25% The closeness of moving parts in a high speed turbine does not permit any axial movement to take place: the axial force or end thrust must therefore be balanced out. Water enters water boxes mounted at opposite ends of the condenser. 4. A turbine operating at optimum conditions will utilise rotating elements (rotor blades) that are designed to move at half of the steam inlet velocity. The other type of turbine, suggested by Giovanni Branca in 1629, is known as the impulse type. Due to their shape, they are referred to as cylinders as well as casings. To prevent the turbine rotor blades from moving outwards similarly and jamming in the casing, an ingenious method is adopted to fix them. a. LABYRINTH PACKING to seal the turbine against the atmosphere is indicated here in section. 4. 2. It is important to distinguish between these two turbines because some modern machines are built on the reaction principle, and others are built to work as impulse turbines. A gravity tank (or tanks) is installed at the top of the power plant building and oil is constantly circulated through the tank to maintain the desired level. The bearings are the only portions of a turbine that require oil, in striking contrast with the reciprocating engine, whether steam or diesel, on which all moving surfaces in contact must be lubricated. 1 0 obj Primary. Each stage has a set of The power developed by the flow in a reaction turbine is also given by the general Euler equation.

/Type /Catalog Steam turbine diaphragms are hollow disc shaped objects that house a turbines stationary blades (fixed blades). c. Sectional. Reduces the size of the thrust on impulse-reaction turbines. In this way, its possible to reduce wear on valve components by having as many valves as possible in the fully closed or fully open position. c. Cylinder.

As the velocity of the steam is directly proportional to the amount of energy transferred to the rotor, the velocity of the steam is increased using nozzles prior to it impinging upon the rotor blades. e. 2,3,4. For a 50% reaction design, the similarity between various angles is 1=2 and 2=1. WebWhy do power plants use steam turbines instead of piston engines. Prior to the steam admission valve there is normally an emergency trip valve which slams shut (closes quickly) in the event of a critical situation occurring. The kinetic energy is regained by the conversion of water into suction head, thereby increasing the total pressure difference on the runner. Combined cycle power plants reclaim waste heat from combustion turbines or from industrial processes that generate significant waste heat e.g. a. a. Chromium Dixon B. The rotor shaft and everything mounted to it (moving blades, rotor discs etc. 2 0 obj 4. e. 1,2,3,4. b. a. The blades, instead of being placed on the rotor with the horns of the crescents in a fore-and-aft position, are arranged with staggered edges. a. Condensers, also sometimes called surface condensers, are large heat exchangers used to cool exhaust steam back into condensate; they are usually installed directly beneath the turbine but may be installed axially in some instances. Steam passes, as indicated by the arrow, through a narrowing orifice and then through a trumpet-shaped opening. The bearing oil system is connected to a trip valve, so that in the event of a supply failure (reduction in oil pressure), the turbine will trip/stop. /Subtype /Image In the impulse turbine the blade-section is crescent-shaped and the space between adjacent blades is symmetrical about its centre. Thus, as previously noted, a reaction turbine is moved primarily by reactive force but also to some extent by direct impulse/thrust. The primary features of the reaction turbine are: only part of the overall pressure drop has occurred up to turbine entry, the remaining pressure drop takes place in the turbine itself; the flow completely fills all of the passages in the runner, unlike the Pelton turbine where, for each jet, only one or two of the buckets at a time are in contact with the water; pivotable guide vanes are used to control and direct the flow; a draft tube is normally added on to the turbine exit; this is considered as an integral part of the turbine. Water content within the steam lines can be monitored by fitting thermocouples to the top and bottom of the steam lines/pipes. e. Are located in the rotor. Place the letter of your choice in the space provided. 2. 1% e. 5%. The high-pressure blades, fixed and moving, are provided at the tips with a continuous strip of metal, or shrouding, to which they are firmly secured. In a steam turbine using velocity compounding _____ expand the steam from initial to exhaust pressure. The standard setup is to have the drive end of the turbine fixed and stationary whilst the opposite end is free to move axially. S.L. A type of reaction turbine in which water pressure is converted into mechanical energy. On start-up WebThe governor is used in the steam turbine to control the speed of the turbine automatically under varying load conditions. Eventually, this leads to a decrease in losses due to turbulence and thus a better head utilization [5]. A turbine with ahead and astern blading will have a dummy piston at either end to ensure balance in either direction of rotation. Another method often used in low-pressure turbines is to make the turbine double flow. There were previously many turbine manufactures such as Pametrada, British Thompson Houston, Parsons, John Brown, Kawasaki, Westinghouse, Curtis, Stal Laval etc. a. Condensing The casing forms the largest pressure boundary of the steam turbine. c. Too expensive to maintain. In ideal conditions the increases in size would be carried out gradually from one end of the turbine to the other; but, for convenience in construction, this is done in suitable steps or stages. d. Rotor. Moving blades are responsible for transferring the heat energy from the steam to the rotor. Rings project from the turbine casing into the rotor grooves and the interior of every ring is sharpened to a knife-edge. Rows of stationary blades alternating with rows of moving However, due to varying load conditions, it is not possible to leave steam throttle valves permanently open, and the valves must at some point be throttled (moved to a position between fully open and fully closed). Keep the rotor in an exact position in the casing. 2. /Type /XObject 1, 2, 3 THE smooth-cased turbine conveys to the uninitiated but little of its hidden might. c. 1,2,3 is connected either directly to the rotor shaft, or, indirectly via a gearbox. This pressure drop gives rise to a reaction in the opposite direction to that of added velocity. Carbon rings, when used for turbine shaft seal require: b. Relieving pressure. Due to the lower pressures, IP blades are not usually fully shrouded. For its proper operation, the turbine is submerged in water in such a way that water enters along the radial axis and after rotating the turbine blades it leaves the turbine vertically through the center of the turbine. b. The use of smaller units reduces the centrifugal forces present on larger units and thus reduces the likelihood of cracking. For reaction less than zero, the rotor has a diffusing action. Despite reaction turbines being classified as reaction, there is always a small degree of force imparted due to impulse. Increase in steam enthalpy. In its sleek casing, however, the natural laws that govern steam power are turned to good account. c. 1,2,3 The Parsons reaction turbine is thus pressure-compounded, but in some recent designs the machines have been built with the high-pressure stages arranged on the velocity-compounded impulse principle and with later stages operated on the pressure-compounded reaction system. 3. One velocity-compounded stages Steam is directed onto the rotor by the fixed vanes or nozzles of the stator.

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