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Bypass Ratio
The bypass ratio (BPR) of a turbofan engine is the ratio between the mass flow rate of the bypass stream to the mass flow rate entering the core. A 10:1 bypass ratio, for example, means that 10 kg of air passes through the bypass duct for every 1 kg of air passing through the core. Turbofan engines are usually described in terms of BPR, which together with engine pressure ratio, turbine inlet temperature and fan pressure ratio are important design parameters. In addition, BPR is quoted for turboprop and unducted fan installations because their high propulsive efficiency gives them the overall efficiency characteristics of very high bypass turbofans. This allows them to be shown together with turbofans on plots which show trends of reducing specific fuel consumption (SFC) with increasing BPR. BPR is also quoted for lift fan installations where the fan airflow is remote from the engine and doesn't physically touch the engine core. Bypass provides a lower fuel consumption ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turbofan
The turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft engine, aircraft propulsion. The word "turbofan" is a portmanteau of "turbine" and "fan": the ''turbo'' portion refers to a gas turbine engine which achieves mechanical energy from combustion, and the ''fan'', a ducted fan that uses the mechanical energy from the gas turbine to force air rearwards. Thus, whereas all the air taken in by a turbojet passes through the combustion chamber and turbines, in a turbofan some of that air bypasses these components. A turbofan thus can be thought of as a turbojet being used to drive a ducted fan, with both of these contributing to the thrust. The ratio of the mass-flow of air bypassing the engine core to the mass-flow of air passing through the core is referred to as the bypass ratio. The engine produces thrust through a combination of these two portions working together; engines that use more Propelling nozzle, jet thrust relative to fan thrust are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propulsive Efficiency
In aerospace engineering, concerning aircraft, rocket and spacecraft design, overall propulsion system efficiency \eta is the efficiency with which the energy contained in a vehicle's fuel is converted into kinetic energy of the vehicle, to accelerate it, or to replace losses due to aerodynamic drag or gravity. Mathematically, it is represented as \eta = \eta_c \eta_p, where \eta_c is the cycle efficiency and \eta_p is the propulsive efficiency. The cycle efficiency is expressed as the percentage of the heat energy in the fuel that is converted to mechanical energy in the engine, and the propulsive efficiency is expressed as the proportion of the mechanical energy actually used to propel the aircraft. The propulsive efficiency is always less than one, because conservation of momentum requires that the exhaust have some of the kinetic energy, and the propulsive mechanism (whether propeller, jet exhaust, or ducted fan) is never perfectly efficient. It is greatly dependent on exhaust ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding the National Advisory Committee for Aeronautics (NACA), to give the U.S. space development effort a distinctly civilian orientation, emphasizing peaceful applications in space science. NASA has since led most American space exploration, including Project Mercury, Project Gemini, the 1968-1972 Apollo Moon landing missions, the Skylab space station, and the Space Shuttle. NASA supports the International Space Station and oversees the development of the Orion spacecraft and the Space Launch System for the crewed lunar Artemis program, Commercial Crew spacecraft, and the planned Lunar Gateway space station. The agency is also responsible for the Launch Services Program, which provides oversight of launch operations and countdown management f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glenn Research Center
NASA John H. Glenn Research Center at Lewis Field is a NASA center within the cities of Brook Park and Cleveland between Cleveland Hopkins International Airport and the Rocky River Reservation of Cleveland Metroparks, with a subsidiary facility in Sandusky, Ohio. Its acting director is James A. Kenyon. Glenn Research Center is one of ten major NASA facilities, whose primary mission is to develop science and technology for use in aeronautics and space. , it employed about 1,650 civil servants and 1,850 support contractors on or near its site. In 2010, the formerly on-site NASA Visitors Center moved to the Great Lakes Science Center in the North Coast Harbor area of downtown Cleveland. History The installation was established in 1942 as part of the National Advisory Committee for Aeronautics (NACA) and was later incorporated into the National Aeronautics and Space Administration as a laboratory for aircraft engine research. It was first named the Aircraft Engine Research L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
School Of Engineering, Massachusetts Institute Of Technology
The MIT School of Engineering (SoE) is one of the five schools of the Massachusetts Institute of Technology, located in Cambridge, Massachusetts, United States. SoE has eight academic departments and two interdisciplinary institutes. The School grants SB, MEng, SM, engineer's degrees, and PhD or ScD degrees. , the Dean of Engineering is Professor Anantha Chandrakasan. The school is the largest at MIT as measured by undergraduate and graduate enrollments and faculty members. Departments and initiatives Departments: * Aeronautics and Astronautics (Course 16) * Biological Engineering (Course 20) * Chemical Engineering (Course 10) * Civil and Environmental Engineering (Course 1) * Electrical Engineering and Computer Science (Course 6, joint department with MIT Schwarzman College of Computing) * Materials Science and Engineering (Course 3) * Mechanical Engineering (Course 2) * Nuclear Science and Engineering (Course 22) Institutes: * Institute for Medical Engineering and Science ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stanford University School Of Engineering
Stanford University School of Engineering is one of the schools of Stanford University. The current dean is Jennifer Widom, the former senior associate dean of faculty affairs and computer science chair. She is the school's 10th dean. List of deans # Theodore J. Hoover (1925–1936) # Samuel B. Morris (1936–1944) # Frederick E. Terman (1944–1958) # Joseph M. Pettit (1958–1972) # William M. Kays (1972–1984) # James F. Gibbons (1984–1996) # John L. Hennessy (1996–1999) # James D. Plummer (1999–2014) # Persis Drell (2014–2016) # Thomas Kenny (interim dean) (2016–2017) # Jennifer Widom (2017–current) Current departments at the school * Aeronautics and Astronautics *Bioengineering and Chemical Engineering (also in the School of Medicine) * Chemical Engineering * Civil and Environmental Engineering * Computer Science * Stanford Department of Electrical Engineering * Materials Science and Engineering * Management Science and Engineering * Mechanical Engineeri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turboprop
A turboprop is a turbine engine that drives an aircraft propeller. A turboprop consists of an intake, reduction gearbox, compressor, combustor, turbine, and a propelling nozzle. Air enters the intake and is compressed by the compressor. Fuel is then added to the compressed air in the combustor, where the fuel-air mixture then combusts. The hot combustion gases expand through the turbine stages, generating power at the point of exhaust. Some of the power generated by the turbine is used to drive the compressor and electric generator. The gases are then exhausted from the turbine. In contrast to a turbojet or turbofan, the engine's exhaust gases do not provide enough energy to create significant thrust, since almost all of the engine's power is used to drive the propeller. Technological aspects Exhaust thrust in a turboprop is sacrificed in favor of shaft power, which is obtained by extracting additional power (beyond that necessary to drive the compressor) from turbine ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fighter Aircraft
Fighter aircraft are fixed-wing military aircraft designed primarily for air-to-air combat. In military conflict, the role of fighter aircraft is to establish air superiority of the battlespace. Domination of the airspace above a battlefield permits bombers and attack aircraft to engage in tactical and strategic bombing of enemy targets. The key performance features of a fighter include not only its firepower but also its high speed and maneuverability relative to the target aircraft. The success or failure of a combatant's efforts to gain air superiority hinges on several factors including the skill of its pilots, the tactical soundness of its doctrine for deploying its fighters, and the numbers and performance of those fighters. Many modern fighter aircraft also have secondary capabilities such as ground attack and some types, such as fighter-bombers, are designed from the outset for dual roles. Other fighter designs are highly specialized while still filling the ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fuel Efficiency
Fuel efficiency is a form of thermal efficiency, meaning the ratio of effort to result of a process that converts chemical potential energy contained in a carrier (fuel) into kinetic energy or work. Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance is often illustrated as a continuous energy profile. Non-transportation applications, such as industry, benefit from increased fuel efficiency, especially fossil fuel power plants or industries dealing with combustion, such as ammonia production during the Haber process. In the context of transport, fuel economy is the energy efficiency of a particular vehicle, given as a ratio of distance traveled per unit of fuel consumed. It is dependent on several factors including engine efficiency, transmission design, and tire design. In most countries, using the metric system, fuel economy is stated as "fuel consumption" in liters per 100 kilometers (L/100 km) or kilometer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jet Airliner
A jet airliner or jetliner is an airliner powered by jet engines (passenger jet aircraft). Airliners usually have two or four jet engines; three-engined designs were popular in the 1970s but are less common today. Airliners are commonly classified as either the large wide-body aircraft A wide-body aircraft, also known as a twin-aisle aircraft, is an airliner with a fuselage wide enough to accommodate two passenger aisles with seven or more seats abreast. The typical fuselage diameter is . In the typical wide-body economy cabi ..., medium narrow-body aircraft and smaller regional jet. Most airliners today are powered by jet engines, because they are capable of safely operating at high speeds and generate sufficient thrust to power large-capacity aircraft. The first jetliners, introduced in the 1950s, used the simpler turbojet engine; these were quickly supplanted by designs using turbofans, which are quieter and more fuel-efficient. History Early history The first air ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rolls-Royce Conway
The Rolls-Royce RB.80 Conway was the first turbofan engine to enter service. Development started at Rolls-Royce in the 1940s, but the design was used only briefly, in the late 1950s and early 1960s, before other turbofan designs replaced it. However, the Conway engine was used in versions of the Handley Page Victor, Vickers VC10, Boeing 707-420 and Douglas DC-8-40. The name "Conway" is the English spelling of the River Conwy, in Wales, in keeping with Rolls' use of river names for gas turbine engines. Development Background Alan Arnold Griffith had proposed a number of different bypass or turbofan engine designs as early as the 1930s while he and Hayne Constant were trying to get their axial-flow jet engines working at the Royal Aircraft Establishment. However, simpler turbojet designs were prioritized during World War II for their use in military applications. Priorities changed dramatically at the end of the war and in 1946 Rolls-Royce agreed that existing engines like the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rolls-Royce Limited
Rolls-Royce was a British luxury car and later an aero-engine manufacturing business established in 1904 in Manchester by the partnership of Charles Rolls and Henry Royce. Building on Royce's good reputation established with his cranes, they quickly developed a reputation for superior engineering by manufacturing the "best car in the world". The business was incorporated as Rolls-Royce Limited in 1906, and a new factory in Derby was opened in 1908. The First World War brought the company into manufacturing aero-engines. Joint development of jet engines began in 1940, and they entered production. Rolls-Royce has built an enduring reputation for development and manufacture of engines for defence and civil aircraft. In the late 1960s, Rolls-Royce was adversely affected by the mismanaged development of its advanced RB211 jet engine and consequent cost over-runs, though it ultimately proved a great success. In 1971, the owners were obliged to liquidate their business. The useful p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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