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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] |
