|
Turbofan Engines
A turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft propulsion. The word "turbofan" is a combination of references to the preceding generation engine technology of the turbojet and the additional fan stage. It consists of a gas turbine engine which achieves mechanical energy from combustion, and 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 jet thrust relative t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquatic Locomotion
Aquatic locomotion or swimming is biologically propulsion , propelled motion through a liquid medium. The simplest propulsive systems are composed of cilia and flagella. Swimming has evolved a number of times in a range of organisms including arthropods, fish, molluscs, amphibians, reptiles, birds, and mammals. Evolution of swimming Swimming evolved a number of times in unrelated lineages. Supposed jellyfish fossils occur in the Ediacaran, but the first free-swimming animals appear in the Early to Middle Cambrian. These are mostly related to the arthropods, and include the Anomalocarididae , Anomalocaridids, which swam by means of lateral lobes in a fashion reminiscent of today's cuttlefish. Cephalopods joined the ranks of the active swimmers (nekton) in the late Cambrian, and chordates were probably swimming from the Early Cambrian. Many terrestrial animals retain some capacity to swim, however some have returned to the water and developed the capacities for aquatic locomotio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jet Noise
In aeroacoustics, jet noise is the field that focuses on the noise generation caused by high-velocity jets and the turbulent eddies generated by shearing flow. Such noise is known as broadband noise and extends well beyond the range of human hearing (100 kHz and higher). Jet noise is also responsible for some of the loudest sounds ever produced by mankind. Sources of jet noise The primary sources of jet noise for a high-speed air jet (meaning when the exhaust velocity exceeds about 100 m/s; 360 km/h; 225 mph) are "jet mixing noise" and, for supersonic flow, shock associated noise. Acoustic sources within the "jet pipe" also contribute to the noise, mainly at lower speeds, which include combustion noise, and sounds produced by interactions of a turbulent stream with fans, compressors, and turbine systems. The jet mixing sound is created by the turbulent mixing of a jet with the ambient fluid, in most cases, air. The mixing initially occurs in an annular s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boeing 747-8 VQ-BSK At LSZH (17754867239)
The Boeing Company, or simply Boeing (), is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, and missiles worldwide. The company also provides leasing and product support services. Boeing is among the largest global aerospace manufacturers; it is the fourth-largest defense contractor in the world based on 2022 revenue and is the largest exporter in the United States by dollar value. Boeing was founded by William E. Boeing in Seattle, Washington, on July 15, 1916. The present corporation is the result of the merger of Boeing with McDonnell Douglas on August 1, 1997. As of 2023, the Boeing Company's corporate headquarters is located in the Crystal City neighborhood of Arlington County, Virginia. The company is organized into three primary divisions: Boeing Commercial Airplanes (BCA), Boeing Defense, Space & Security (BDS), and Boeing Global Services (BGS). In 2021, Boeing recorded $62.3billion in sales. Boei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Effective Exhaust Velocity
Specific impulse (usually abbreviated ) is a measure of how efficiently a reaction mass engine, such as a rocket using propellant or a jet engine using fuel, generates thrust. In general, this is a ratio of the '' impulse'', i.e. change in momentum, ''per mass'' of propellant. This is equivalent to "thrust per massflow". The resulting unit is equivalent to velocity. If the engine expels mass at a constant exhaust velocity v_e then the thrust will be \mathbf = v_e \frac . If we integrate over time to get the total change in momentum, and then divide by the mass, we see that the specific impulse is equal to the exhaust velocity v_e . In practice, the specific impulse is usually lower than the actual physical exhaust velocity inefficiencies in the rocket, and thus corresponds to an "effective" exhaust velocity. That is, the specific impulse I_ in units of velocity *is defined by* : \mathbf = I_ \frac , where \mathbf is the average thrust. The practical meaning of the me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SRM Institute Of Science And Technology
SRM Institute of Science and Technology (SRMIST) is a private deemed university located in Kattankulathur, (near Chennai), Tamil Nadu, India. Founded in 1985 as SRM Engineering College in Kattankulathur, it gained the deemed University status in 2002. SRM Institute of Science and Technology is spread across five campuses — Chennai (Kattankulathur, Ramapuram, Vadapalani), Ghaziabad and Tiruchirappalli. Those are all same University as per section 3 of University Grants Commission Act, 1956. It has three sister universities in Andhra Pradesh, Haryana and Sikkim. History SRM (Sri Ramaswamy Memorial) Engineering College, was established in 1985, followed by the other SRM colleges from 1992 to 1997. The institute gained deemed status in 2002 as SRM Institute of Science and Technology and renamed SRM University in 2006. In 2017, its name was reverted to SRM Institute of Science and Technology following UGC's order to drop "University" from the name. Campuses Located about ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turboprop
A turboprop is a Gas turbine, gas turbine engine that drives an aircraft Propeller (aeronautics), propeller. A turboprop consists of an intake, reduction drive, reduction gearbox, gas compressor, 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 mixture, fuel-air mixture then Combustion, 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 power 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 obtaine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propelling Nozzle
A propelling nozzle or exhaust ejector is a nozzle that converts the internal energy of a working gas into propulsive force; it is the nozzle, which forms a jet, that separates a gas turbine, or gas generator, from a jet engine. Propelling nozzles accelerate the available gas to subsonic, transonic, or supersonic velocities depending on the power setting of the engine, their internal shape and the pressures at entry to, and exit from, the nozzle. The internal shape may be convergent or convergent-divergent (C-D). C-D nozzles can accelerate the jet to supersonic velocities within the divergent section, whereas a convergent nozzle cannot accelerate the jet beyond sonic speed. Propelling nozzles may have a fixed geometry, or they may have variable geometry to give different exit areas to control the operation of the engine when equipped with an afterburner or a reheat system. When afterburning engines are equipped with a C-D nozzle the throat area is variable. Nozzles for superso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propeller (aeronautics)
In aeronautics, an aircraft propeller, also called an airscrew,Beaumont, R.A.; ''Aeronautical Engineering'', Odhams, 1942, Chapter 13, "Airscrews". converts rotary motion from an Aircraft engine, engine or other power source into a swirling slipstream which pushes the propeller forwards or backwards. It comprises a rotating power-driven hub, to which are attached several radial airfoil-section blades such that the whole assembly rotates about a longitudinal axis. The blade pitch may be fixed, manually variable to a few set positions, or of the automatically variable "constant-speed" type. The propeller attaches to the power source's driveshaft either directly or through Propeller speed reduction unit, reduction gearing. Propellers can be made from wood, metal or composite materials. Propellers are most suitable for use at subsonic airspeeds generally below about , although supersonic speeds were achieved in the McDonnell XF-88B experimental propeller-equipped aircraft. Supersonic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gas Turbine Efficiency
Gas is a state of matter that has neither a fixed volume nor a fixed shape and is a compressible fluid. A ''pure gas'' is made up of individual atoms (e.g. a noble gas like neon) or molecules of either a single type of atom ( elements such as oxygen) or from different atoms ( compounds such as carbon dioxide). A ''gas mixture'', such as air, contains a variety of pure gases. What distinguishes gases from liquids and solids is the vast separation of the individual gas particles. This separation can make some gases invisible to the human observer. The gaseous state of matter occurs between the liquid and plasma states, the latter of which provides the upper-temperature boundary for gases. Bounding the lower end of the temperature scale lie degenerative quantum gases which are gaining increasing attention. High-density atomic gases super-cooled to very low temperatures are classified by their statistical behavior as either Bose gases or Fermi gases. For a comprehensive listing of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pratt & Whitney J58
The Pratt & Whitney J58 (company designation JT11D-20) is an American jet engine that powered the Lockheed A-12, and subsequently the Lockheed YF-12, YF-12 and the Lockheed SR-71 Blackbird, SR-71 aircraft. It was an afterburning turbojet engine with a unique compressor bleed to the afterburner that gave increased thrust at high speeds. Because of the wide speed range of the aircraft, the engine needed two modes of operation to take it from stationary on the ground to at altitude. It was a conventional afterburning turbojet for take-off and acceleration to Mach 2 and then used bleed air, permanent compressor bleed to the afterburner above Mach 2. The way the engine worked at cruise led it to be described as "acting like a turboramjet". It has also been described as a turboramjet based on incorrect statements describing the turbomachinery as being completely bypassed. The engine performance that met the mission requirements for the CIA and USAF over many years was later enhanced ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compressor Stall
A compressor stall is a local disruption of the airflow in the compressor of a gas turbine or turbocharger. A stall that results in the complete disruption of the airflow through the compressor is referred to as a compressor surge. The severity of the phenomenon ranges from a momentary power drop barely registered by the engine instruments to a complete loss of compression in case of a surge, requiring adjustments in the fuel flow to recover normal operation. Compressor stalls were a common problem on early jet engines with simple aerodynamics and manual or mechanical fuel control units, but they have been virtually eliminated by better design and the use of hydromechanical and electronic control systems such as full authority digital engine control. Modern compressors are carefully designed and controlled to avoid or limit stall within an engine's operating range. Types There are two types of compressor stall: Rotating stall Rotating stall is a local disruption of airflow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
