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70-607: The AI-20 was the first gas turbine engine developed by the design bureau led by Oleksandr Heorhiiovych Ivchenko based at Zaporizhzhia , USSR , which had previously concentrated on small piston engines such as the Ivchenko AI-14 and AI-26 radials . It was designed as a prospective powerplant for the new, large Ilyushin Il-18 airliner and the Antonov An-10 , to be powered by four turboprops , in competition with

140-582: A problem for the passengers. As mentioned, the overhaul life of the engine was initially poor compared with contemporary western engines, being reported as 600–750 hours in 1964, but was later improved by continuous development to 8,000 hours, with a service life of 22,000 hours in the AI-20D series 5M. Serial production was carried out at Zaporizhzhia ( Motor Sich ) and at Perm Engine Plant ( UEC-Perm Engines ), USSR in 1958, also being built under licence in China as

210-422: A turbine . Also, in thermodynamic cycles energy may be input to the working fluid by means of a compressor . The mathematical formulation for this may be quite simple if we consider a cylinder in which a working fluid resides. A piston is used to input useful work to the fluid. From mechanics, the work done from state 1 to state 2 of the process is given by: where ds is the incremental distance from one state to

280-415: A turbojet , driving the fan of a turbofan , rotor or accessory of a turboshaft , and gear reduction and propeller of a turboprop . If the engine has a power turbine added to drive an industrial generator or a helicopter rotor, the exit pressure will be as close to the entry pressure as possible with only enough energy left to overcome the pressure losses in the exhaust ducting and expel the exhaust. For

350-409: A turboprop engine there will be a particular balance between propeller power and jet thrust which gives the most economical operation. In a turbojet engine only enough pressure and energy is extracted from the flow to drive the compressor and other components. The remaining high-pressure gases are accelerated through a nozzle to provide a jet to propel an aircraft. The smaller the engine, the higher

420-420: A turbopump to permit the use of lightweight, low-pressure tanks, reducing the empty weight of the rocket. A turboprop engine is a turbine engine that drives an aircraft propeller using a reduction gear to translate high turbine section operating speed (often in the 10s of thousands) into low thousands necessary for efficient propeller operation. The benefit of using the turboprop engine is to take advantage of

490-452: A turboshaft design. They supply: Industrial gas turbines differ from aeronautical designs in that the frames, bearings, and blading are of heavier construction. They are also much more closely integrated with the devices they power—often an electric generator —and the secondary-energy equipment that is used to recover residual energy (largely heat). They range in size from portable mobile plants to large, complex systems weighing more than

560-413: A buildup on the outside of the blades. Nickel-based superalloys boast improved strength and creep resistance due to their composition and resultant microstructure . The gamma (γ) FCC nickel is alloyed with aluminum and titanium in order to precipitate a uniform dispersion of the coherent Ni 3 (Al,Ti) gamma-prime (γ') phases. The finely dispersed γ' precipitates impede dislocation motion and introduce

630-461: A centrifugal or axial compressor ). Heat is added in the combustion chamber and the specific volume of the gas increases, accompanied by a slight loss in pressure. During expansion through the stator and rotor passages in the turbine, irreversible energy transformation once again occurs. Fresh air is taken in, in place of the heat rejection. Air is taken in by a compressor, called a gas generator , with either an axial or centrifugal design, or

700-421: A combination of the two. This air is then ducted into the combustor section which can be of a annular , can , or can-annular design. In the combustor section, roughly 70% of the air from the compressor is ducted around the combustor itself for cooling purposes. The remaining roughly 30% the air is mixed with fuel and ignited by the already burning air-fuel mixture , which then expands producing power across

770-425: A compressor where its pressure is increased. The compressor therefore inputs work to the working fluid (positive work). The fluid is then transferred to a combustion chamber where this time heat energy is input by means of the burning of a fuel. The air then expands in a turbine thus doing work against the surroundings (negative work). Different working fluids have different properties and in choosing one in particular

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840-426: A diameter of 4.5 meters (14 feet 9 inches), featuring prominent propeller spinners , and hydraulic actuation for prop pitch. The engines were mounted above the wing and featured integrated fire extinguishers. The engines were started with electric motors, the power for the motors being provided by a ground cart. The AI-20 is a single-shaft turboprop with a ten-stage axial compressor and a three-stage power turbine, and

910-517: A few dozen hours per year—depending on the electricity demand and the generating capacity of the region. In areas with a shortage of base-load and load following power plant capacity or with low fuel costs, a gas turbine powerplant may regularly operate most hours of the day. A large single-cycle gas turbine typically produces 100 to 400 megawatts of electric power and has 35–40% thermodynamic efficiency . Industrial gas turbines that are used solely for mechanical drive or used in collaboration with

980-579: A gas turbine engine is its power to weight ratio. Since significant useful work can be generated by a relatively lightweight engine, gas turbines are perfectly suited for aircraft propulsion. Thrust bearings and journal bearings are a critical part of a design. They are hydrodynamic oil bearings or oil-cooled rolling-element bearings . Foil bearings are used in some small machines such as micro turbines and also have strong potential for use in small gas turbines/ auxiliary power units A major challenge facing turbine design, especially turbine blades ,

1050-490: A hundred tonnes housed in purpose-built buildings. When the gas turbine is used solely for shaft power, its thermal efficiency is about 30%. However, it may be cheaper to buy electricity than to generate it. Therefore, many engines are used in CHP (Combined Heat and Power) configurations that can be small enough to be integrated into portable container configurations. Gas turbines can be particularly efficient when waste heat from

1120-418: A lesser extent, on cars, buses, and motorcycles. A key advantage of jets and turboprops for airplane propulsion – their superior performance at high altitude compared to piston engines, particularly naturally aspirated ones – is irrelevant in most automobile applications. Their power-to-weight advantage, though less critical than for aircraft, is still important. Gas turbines offer a high-powered engine in

1190-429: A propeller ( turboprop ) or ducted fan ( turbofan ) to reduce fuel consumption (by increasing propulsive efficiency) at subsonic flight speeds. An extra turbine is also required to drive a helicopter rotor or land-vehicle transmission ( turboshaft ), marine propeller or electrical generator (power turbine). Greater thrust-to-weight ratio for flight is achieved with the addition of an afterburner . The basic operation of

1260-532: A recovery steam generator differ from power generating sets in that they are often smaller and feature a dual shaft design as opposed to a single shaft. The power range varies from 1 megawatt up to 50 megawatts. These engines are connected directly or via a gearbox to either a pump or compressor assembly. The majority of installations are used within the oil and gas industries. Mechanical drive applications increase efficiency by around 2%. Oil and gas platforms require these engines to drive compressors to inject gas into

1330-425: A refrigeration unit, the working fluid is called the refrigerant. Ammonia is a typical refrigerant and may be used as the primary working fluid. Compared with water (which can also be used as a refrigerant), ammonia makes use of relatively high pressures requiring more robust and expensive equipment. In air standard cycles as in gas turbine cycles, the working fluid is air. In the open cycle gas turbine, air enters

1400-536: A takeoff power of 2,985 kW (4,000 shp) and sustained power of 2,090 kW (2,800 shp) at cruise altitude. Early Il-18A production had initially been fitted with Kuznetsov NK-4 engines, but they were soon exchanged for AI-20s. Later Il-18B production featured AI-20A Series 2 engines, with the same power ratings, but with technical improvements, thus older machines were updated with the Series 2 powerplants. The AI-20s drove four-bladed variable pitch reversible props with

1470-495: A thermodynamic cycle it may be the case that the working fluid changes state from gas to liquid or vice versa. Certain gases such as helium can be treated as ideal gases . This is not generally the case for superheated steam and the ideal gas equation does not really hold. At much higher temperatures however it still yields relatively accurate results. The physical and chemical properties of the working fluid are extremely important when designing thermodynamic systems. For instance, in

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1540-569: A threshold stress, increasing the stress required for the onset of creep. Furthermore, γ' is an ordered L1 2 phase that makes it harder for dislocations to shear past it. Further Refractory elements such as rhenium and ruthenium can be added in solid solution to improve creep strength. The addition of these elements reduces the diffusion of the gamma prime phase, thus preserving the fatigue resistance, strength, and creep resistance. The development of single crystal superalloys has led to significant improvements in creep resistance as well. Due to

1610-550: A very small and light package. However, they are not as responsive and efficient as small piston engines over the wide range of RPMs and powers needed in vehicle applications. In series hybrid vehicles, as the driving electric motors are mechanically detached from the electricity generating engine, the responsiveness, poor performance at low speed and low efficiency at low output problems are much less important. The turbine can be run at optimum speed for its power output, and batteries and ultracapacitors can supply power as needed, with

1680-497: Is designed to run at a constant speed. A big problem with early production engines was the poor reliability of the AI-20 engines, which had a time between overhauls (TBO) in the range of 600 to 750 hours. The AI-20K engine variant was finally introduced, with a TBO of 2,000 hours – unimpressive by modern standards, but a big improvement. One issue that was never addressed was noise; turboprops are relatively noisy and high noise levels were

1750-841: Is reduced.) For passive heat transfer , a working fluid is a gas or liquid, usually called a coolant or heat transfer fluid, that primarily transfers heat into or out of a region of interest by conduction , convection , and/or forced convection (pumped liquid cooling , air cooling , etc.). The working fluid of a heat engine or heat pump is a gas or liquid, usually called a refrigerant , coolant, or working gas, that primarily converts thermal energy (temperature change) into mechanical energy (or vice versa) by phase change and/or heat of compression and expansion. Examples using phase change include water↔steam in steam engines , and refrigerants in vapor-compression refrigeration and air conditioning systems. Examples without phase change include air or hydrogen in hot air engines such as

1820-677: Is reducing the creep that is induced by the high temperatures and stresses that are experienced during operation. Higher operating temperatures are continuously sought in order to increase efficiency, but come at the cost of higher creep rates. Several methods have therefore been employed in an attempt to achieve optimal performance while limiting creep, with the most successful ones being high performance coatings and single crystal superalloys . These technologies work by limiting deformation that occurs by mechanisms that can be broadly classified as dislocation glide, dislocation climb and diffusional flow. Protective coatings provide thermal insulation of

1890-475: Is used, it is possible to use exhaust air from the turbine as the primary combustion air. This effectively reduces global heat losses, although heat losses associated with the combustion exhaust remain inevitable. Closed-cycle gas turbines based on helium or supercritical carbon dioxide also hold promise for use with future high temperature solar and nuclear power generation. Gas turbines are often used on ships , locomotives , helicopters , tanks , and to

1960-968: The Airbus A400M transport, Lockheed AC-130 and the 60-year-old Tupolev Tu-95 strategic bomber. While military turboprop engines can vary, in the civilian market there are two primary engines to be found: the Pratt & Whitney Canada PT6 , a free-turbine turboshaft engine, and the Honeywell TPE331 , a fixed turbine engine (formerly designated as the Garrett AiResearch 331). Aeroderivative gas turbines are generally based on existing aircraft gas turbine engines and are smaller and lighter than industrial gas turbines. Aeroderivatives are used in electrical power generation due to their ability to be shut down and handle load changes more quickly than industrial machines. They are also used in

2030-528: The BMW 801 . This, however, also translated into poor efficiency and reliability. More advanced gas turbines (such as those found in modern jet engines or combined cycle power plants) may have 2 or 3 shafts (spools), hundreds of compressor and turbine blades, movable stator blades, and extensive external tubing for fuel, oil and air systems; they use temperature resistant alloys, and are made with tight specifications requiring precision manufacture. All this often makes

2100-505: The Brayton cycle , also known as the "constant pressure cycle" . It is distinguished from the Otto cycle , in that all the processes (compression, ignition combustion, exhaust), occur at the same time, continuously. In a real gas turbine, mechanical energy is changed irreversibly (due to internal friction and turbulence) into pressure and thermal energy when the gas is compressed (in either

2170-649: The Kuznetsov NK-4 engines . Both engines were tested on the preproduction batch of 20 Il-18s, but the Ivchenko engine was chosen for full production, possibly due to a crash caused by an inflight failure of an NK-4 engine, and possibly due to the desire for the engines of the Ukrainian An-10 to also be built in Ukraine. The Il-18B was powered by four Ivchenko AI-20A Series 1 turboprops, each providing

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2240-700: The Stirling engine , air or gases in gas-cycle heat pumps , etc. (Some heat pumps and heat engines use "working solids", such as rubber bands, for elastocaloric refrigeration or thermoelastic cooling and nickel titanium in a prototype heat engine.) Working fluids other than air or water are necessarily recirculated in a loop. Some hydraulic and passive heat-transfer systems are open to the water supply and/or atmosphere, sometimes through breather filters . Heat engines, heat pumps, and systems using volatile liquids or special gases are usually sealed behind relief valves . The working fluid's properties are essential for

2310-531: The WJ-6 . About 14,000 AI-20s have been built in total. Data from Jane's All The World's Aircraft 1993–94, Motor Sich website, Aircraft engines of the World 1970 Comparable engines Related lists Gas turbine A gas turbine or gas turbine engine is a type of continuous flow internal combustion engine . The main parts common to all gas turbine engines form the power-producing part (known as

2380-434: The turbine . This expansion of the mixture then leaves the combustor section and has its velocity increased across the turbine section to strike the turbine blades, spinning the disc they are attached to, thus creating useful power. Of the power produced, 60-70% is solely used to power the gas generator. The remaining power is used to power what the engine is being used for, typically an aviation application, being thrust in

2450-456: The active species (typically vacancies) within the alloy and reducing dislocation and vacancy creep. It has been found that a coating of 1–200 μm can decrease blade temperatures by up to 200 °C (392 °F). Bond coats are directly applied onto the surface of the substrate using pack carburization and serve the dual purpose of providing improved adherence for the TBC and oxidation resistance for

2520-510: The addition of a ducted fan are called turbofans or (rarely) fan-jets. These engines produce nearly 80% of their thrust by the ducted fan, which can be seen from the front of the engine. They come in two types, low-bypass turbofan and high bypass , the difference being the amount of air moved by the fan, called "bypass air". These engines offer the benefit of more thrust without extra fuel consumption. Gas turbines are also used in many liquid-fuel rockets , where gas turbines are used to power

2590-401: The blade and offer oxidation and corrosion resistance. Thermal barrier coatings (TBCs) are often stabilized zirconium dioxide -based ceramics and oxidation/corrosion resistant coatings (bond coats) typically consist of aluminides or MCrAlY (where M is typically Fe and/or Cr) alloys. Using TBCs limits the temperature exposure of the superalloy substrate, thereby decreasing the diffusivity of

2660-420: The closely related form of the turbocharger . The turbocharger is basically a compact and simple free shaft radial gas turbine which is driven by the piston engine's exhaust gas . The centripetal turbine wheel drives a centrifugal compressor wheel through a common rotating shaft. This wheel supercharges the engine air intake to a degree that can be controlled by means of a wastegate or by dynamically modifying

2730-473: The compressor and the turbine with a compressed air store. In a conventional turbine, up to half the generated power is used driving the compressor. In a compressed air energy storage configuration, power is used to drive the compressor, and the compressed air is released to operate the turbine when required. Turboshaft engines are used to drive compressors in gas pumping stations and natural gas liquefaction plants. They are also used in aviation to power all but

2800-513: The compressor/shaft/turbine rotor assembly, with other moving parts in the fuel system. This, in turn, can translate into price. For instance, costing 10,000  ℛℳ for materials, the Jumo 004 proved cheaper than the Junkers 213 piston engine, which was 35,000  ℛℳ , and needed only 375 hours of lower-skill labor to complete (including manufacture, assembly, and shipping), compared to 1,400 for

2870-444: The construction of a simple gas turbine more complicated than a piston engine. Moreover, to reach optimum performance in modern gas turbine power plants the gas needs to be prepared to exact fuel specifications. Fuel gas conditioning systems treat the natural gas to reach the exact fuel specification prior to entering the turbine in terms of pressure, temperature, gas composition, and the related Wobbe index . The primary advantage of

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2940-425: The early 2020s. In March 2018, GE Power achieved a 63.08% gross efficiency for its 7HA turbine. Aeroderivative gas turbines can also be used in combined cycles, leading to a higher efficiency, but it will not be as high as a specifically designed industrial gas turbine. They can also be run in a cogeneration configuration: the exhaust is used for space or water heating, or drives an absorption chiller for cooling

3010-435: The engine cycled on and off to run it only at high efficiency. The emergence of the continuously variable transmission may also alleviate the responsiveness problem. Turbines have historically been more expensive to produce than piston engines, though this is partly because piston engines have been mass-produced in huge quantities for decades, while small gas turbine engines are rarities; however, turbines are mass-produced in

3080-617: The engine's crankshaft instead of to a centrifugal compressor, thus providing additional power instead of boost. While the turbocharger is a pressure turbine, a power recovery turbine is a velocity one. Working fluid For fluid power , a working fluid is a gas or liquid that primarily transfers force , motion , or mechanical energy . In hydraulics , water or hydraulic fluid transfers force between hydraulic components such as hydraulic pumps , hydraulic cylinders , and hydraulic motors that are assembled into hydraulic machinery , hydraulic drive systems , etc. In pneumatics ,

3150-533: The entire engine from raw materials, including the fabrication of a centrifugal compressor wheel from plywood, epoxy and wrapped carbon fibre strands. Several small companies now manufacture small turbines and parts for the amateur. Most turbojet-powered model aircraft are now using these commercial and semi-commercial microturbines, rather than a Schreckling-like home-build. Small gas turbines are used as auxiliary power units (APUs) to supply auxiliary power to larger, mobile, machines such as an aircraft , and are

3220-407: The exhaust gases, or from ducted fans connected to the gas turbines. Jet engines that produce thrust from the direct impulse of exhaust gases are often called turbojets . While still in service with many militaries and civilian operators, turbojets have mostly been phased out in favor of the turbofan engine due to the turbojet's low fuel efficiency, and high noise. Those that generate thrust with

3290-399: The full description of thermodynamic systems. Although working fluids have many physical properties which can be defined, the thermodynamic properties which are often required in engineering design and analysis are few. Pressure , temperature , enthalpy , entropy , specific volume , and internal energy are the most common. If at least two thermodynamic properties are known, the state of

3360-414: The gas generator or core) and are, in the direction of flow: Additional components have to be added to the gas generator to suit its application. Common to all is an air inlet but with different configurations to suit the requirements of marine use, land use or flight at speeds varying from stationary to supersonic. A propelling nozzle is added to produce thrust for flight. An extra turbine is added to drive

3430-408: The gas turbine is a Brayton cycle with air as the working fluid : atmospheric air flows through the compressor that brings it to higher pressure; energy is then added by spraying fuel into the air and igniting it so that the combustion generates a high-temperature flow; this high-temperature pressurized gas enters a turbine, producing a shaft work output in the process, used to drive the compressor;

3500-550: The hobby of engine collecting. In its most extreme form, amateurs have even rebuilt engines beyond professional repair and then used them to compete for the land speed record. The simplest form of self-constructed gas turbine employs an automotive turbocharger as the core component. A combustion chamber is fabricated and plumbed between the compressor and turbine sections. More sophisticated turbojets are also built, where their thrust and light weight are sufficient to power large model aircraft. The Schreckling design constructs

3570-435: The inlet air and increase the power output, technology known as turbine inlet air cooling . Another significant advantage is their ability to be turned on and off within minutes, supplying power during peak, or unscheduled, demand. Since single cycle (gas turbine only) power plants are less efficient than combined cycle plants, they are usually used as peaking power plants , which operate anywhere from several hours per day to

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3640-617: The lack of grain boundaries, single crystals eliminate Coble creep and consequently deform by fewer modes – decreasing the creep rate. Although single crystals have lower creep at high temperatures, they have significantly lower yield stresses at room temperature where strength is determined by the Hall-Petch relationship. Care needs to be taken in order to optimize the design parameters to limit high temperature creep while not decreasing low temperature yield strength. Airbreathing jet engines are gas turbines optimized to produce thrust from

3710-550: The marine industry to reduce weight. Common types include the General Electric LM2500 , General Electric LM6000 , and aeroderivative versions of the Pratt & Whitney PW4000 , Pratt & Whitney FT4 and Rolls-Royce RB211 . Increasing numbers of gas turbines are being used or even constructed by amateurs. In its most straightforward form, these are commercial turbines acquired through military surplus or scrapyard sales, then operated for display as part of

3780-403: The next and F is the force applied. The negative sign is introduced since in this case a decrease in volume is being considered. The situation is shown in the following figure: The force is given by the product of the pressure in the cylinder and its cross sectional area such that Where A⋅ds = dV is the elemental change of cylinder volume. If from state 1 to 2 the volume increases then

3850-467: The pioneer of modern Micro-Jets, Kurt Schreckling , produced one of the world's first Micro-Turbines, the FD3/67. This engine can produce up to 22 newtons of thrust, and can be built by most mechanically minded people with basic engineering tools, such as a metal lathe . Evolved from piston engine turbochargers , aircraft APUs or small jet engines , microturbines are 25 to 500 kilowatt turbines

3920-474: The purpose of using pulverized coal or finely ground biomass (such as sawdust) as a fuel. In the indirect system, a heat exchanger is used and only clean air with no combustion products travels through the power turbine. The thermal efficiency is lower in the indirect type of external combustion; however, the turbine blades are not subjected to combustion products and much lower quality (and therefore cheaper) fuels are able to be used. When external combustion

3990-670: The rotation rate of the shaft must be to attain the required blade tip speed. Blade-tip speed determines the maximum pressure ratios that can be obtained by the turbine and the compressor. This, in turn, limits the maximum power and efficiency that can be obtained by the engine. In order for tip speed to remain constant, if the diameter of a rotor is reduced by half, the rotational speed must double. For example, large jet engines operate around 10,000–25,000 rpm, while micro turbines spin as fast as 500,000 rpm. Mechanically, gas turbines can be considerably less complex than Reciprocating engines . Simple turbines might have one main moving part,

4060-573: The shaft work is achieved. The fourth step of the Brayton cycle (cooling of the working fluid) is omitted, as gas turbines are open systems that do not reuse the same air. Gas turbines are used to power aircraft, trains, ships, electrical generators, pumps, gas compressors, and tanks . In an ideal gas turbine, gases undergo four thermodynamic processes: an isentropic compression, an isobaric (constant pressure) combustion, an isentropic expansion and isobaric heat rejection. Together, these make up

4130-545: The size of a refrigerator . Microturbines have around 15% efficiencies without a recuperator , 20 to 30% with one and they can reach 85% combined thermal-electrical efficiency in cogeneration . Most gas turbines are internal combustion engines but it is also possible to manufacture an external combustion gas turbine which is, effectively, a turbine version of a hot air engine . Those systems are usually indicated as EFGT (Externally Fired Gas Turbine) or IFGT (Indirectly Fired Gas Turbine). External combustion has been used for

4200-503: The smallest modern helicopters, and function as an auxiliary power unit in large commercial aircraft. A primary shaft carries the compressor and its turbine which, together with a combustor, is called a Gas Generator . A separately spinning power-turbine is usually used to drive the rotor on helicopters. Allowing the gas generator and power turbine/rotor to spin at their own speeds allows more flexibility in their design. Also known as miniature gas turbines or micro-jets. With this in mind

4270-511: The substrate. The Al from the bond coats forms Al 2 O 3 on the TBC-bond coat interface which provides the oxidation resistance, but also results in the formation of an undesirable interdiffusion (ID) zone between itself and the substrate. The oxidation resistance outweighs the drawbacks associated with the ID zone as it increases the lifetime of the blade and limits the efficiency losses caused by

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4340-405: The thermodynamic properties of the fluid. In reality however this can only be done if the process is reversible . If not, the changes in property are represented as a dotted line on a property diagram. This issue does not really affect thermodynamic analysis since in most cases it is the end states of a process which are sought after. The working fluid can be used to output useful work if used in

4410-595: The turbine engines high power-to-weight ratio to drive a propeller, thus allowing a more powerful, but also smaller engine to be used. Turboprop engines are used on a wide range of business aircraft such as the Pilatus PC-12 , commuter aircraft such as the Beechcraft 1900 , and small cargo aircraft such as the Cessna 208 Caravan or De Havilland Canada Dash 8 , and large aircraft (typically military) such as

4480-463: The turbine housing's geometry (as in a variable geometry turbocharger ). It mainly serves as a power recovery device which converts a great deal of otherwise wasted thermal and kinetic energy into engine boost. Turbo-compound engines (actually employed on some semi-trailer trucks ) are fitted with blow down turbines which are similar in design and appearance to a turbocharger except for the turbine shaft being mechanically or hydraulically connected to

4550-480: The turbine is recovered by a heat recovery steam generator (HRSG) to power a conventional steam turbine in a combined cycle configuration. The 605 MW General Electric 9HA achieved a 62.22% efficiency rate with temperatures as high as 1,540 °C (2,800 °F). For 2018, GE offers its 826 MW HA at over 64% efficiency in combined cycle due to advances in additive manufacturing and combustion breakthroughs, up from 63.7% in 2017 orders and on track to achieve 65% by

4620-408: The unused energy comes out in the exhaust gases that can be repurposed for external work, such as directly producing thrust in a turbojet engine , or rotating a second, independent turbine (known as a power turbine ) that can be connected to a fan, propeller, or electrical generator. The purpose of the gas turbine determines the design so that the most desirable split of energy between the thrust and

4690-498: The wells to force oil up via another bore, or to compress the gas for transportation. They are also often used to provide power for the platform. These platforms do not need to use the engine in collaboration with a CHP system due to getting the gas at an extremely reduced cost (often free from burn off gas). The same companies use pump sets to drive the fluids to land and across pipelines in various intervals. One modern development seeks to improve efficiency in another way, by separating

4760-451: The working fluid actually does work on its surroundings and this is commonly denoted by a negative work. If the volume decreases the work is positive. By the definition given with the above integral the work done is represented by the area under a pressure–volume diagram . If we consider the case where we have a constant pressure process then the work is simply given by Depending on the application, various types of working fluids are used. In

4830-399: The working fluid can be defined. This is usually done on a property diagram which is simply a plot of one property versus another. When the working fluid passes through engineering components such as turbines and compressors , the point on a property diagram moves due to the possible changes of certain properties. In theory therefore it is possible to draw a line/curve which fully describes

4900-464: The working fluid is air or another gas which transfers force between pneumatic components such as compressors , vacuum pumps , pneumatic cylinders , and pneumatic motors . In pneumatic systems, the working gas also stores energy because it is compressible. (Gases also heat up as they are compressed and cool as they expand; this incidental heat pump is rarely exploited.) (Some gases also condense into liquids as they are compressed and boil as pressure

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