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Exhaust Mixer
In aviation, exhaust mixer is a feature of many turbofan engines, where the bypass (cold/slow) air is mixed with the core (hot/fast) exhaust gases, before exhausting to atmospheric pressure through a common (mixed flow) propelling nozzle. Benefits The mixer reduces the velocity of the core exiting air, and consequently, reducing the amount of noise produced. Additionally, the temperature of the exhaust is reduced, contributing to the overall reduction of the thermal signature of the aircraft. This attribute is critical in military aircraft where thermal detection or heat-seeking weapons are used. Ideally, a mixer is also a performance benefit to increasing thrust. The exhaust thrust from a jet engine is equal to exhaust mass flow times exhaust velocity, i.e., ''Thrust = ṁv'', while the energy to make that thrust is given by ''Energy'' = 1/2''mv''2. A mixer helps reduce the fastest exhaust velocities from the core of the engine, while making the average exhaust velocity faste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boeing 737-2B7-Adv, Dasab Airlines AN0992824
The Boeing Company () is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, telecommunications equipment, and missiles worldwide. The company also provides leasing and product support services. Boeing is among the largest global aerospace manufacturers; it is the third-largest defense contractor in the world based on 2020 revenue, and is the largest exporter in the United States by dollar value. Boeing stock is included in the Dow Jones Industrial Average. Boeing is incorporated in Delaware. Boeing was founded by William 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. Then chairman and CEO of Boeing, Philip M. Condit, assumed those roles in the combined company, while Harry Stonecipher, former CEO of McDonnell Douglas, became president and COO. The Boeing Company's corporate headquarters is in Chicago, Illi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turbofan Engine
The turbofan or fanjet is a type of airbreathing jet engine that is widely used in 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 jet thrust relative to fan thrust are known as ''low-bypass turbofans' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exhaust Gas
Exhaust gas or flue gas is emitted as a result of the combustion of fuels such as natural gas, gasoline (petrol), diesel fuel, fuel oil, biodiesel blends, or coal. According to the type of engine, it is discharged into the atmosphere through an exhaust pipe, flue gas stack, or propelling nozzle. It often disperses downwind in a pattern called an ''exhaust plume''. It is a major component of motor vehicle emissions (and from stationary internal combustion engines), which can also include crankcase blow-by and evaporation of unused gasoline. Motor vehicle emissions contribute to air pollution and are a major ingredient in the creation of smog in some large cities. A 2013 study by the Massachusetts Institute of Technology (MIT) indicates that 53,000 early deaths occur per year in the United States alone because of vehicle emissions. According to another study from the same university, traffic fumes alone cause the death of 5,000 people every year just in the United Kingdom. Comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nozzle
A nozzle is a device designed to control the direction or characteristics of a fluid flow (specially to increase velocity) as it exits (or enters) an enclosed chamber or pipe. A nozzle is often a pipe or tube of varying cross sectional area, and it can be used to direct or modify the flow of a fluid (liquid or gas). Nozzles are frequently used to control the rate of flow, speed, direction, mass, shape, and/or the pressure of the stream that emerges from them. In a nozzle, the velocity of fluid increases at the expense of its pressure energy. Types Jet A gas jet, fluid jet, or hydro jet is a nozzle intended to eject gas or fluid in a coherent stream into a surrounding medium. Gas jets are commonly found in gas stoves, ovens, or barbecues. Gas jets were commonly used for light before the development of electric light. Other types of fluid jets are found in carburetors, where smooth calibrated orifices are used to regulate the flow of fuel into an engine, and in jacuzzis or spa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Convair 880 Lisa Marie Graceland Memphis TN 2013-04-01 028
Convair, previously Consolidated Vultee, was an American aircraft manufacturing company that later expanded into rockets and spacecraft. The company was formed in 1943 by the merger of Consolidated Aircraft and Vultee Aircraft. In 1953, it was purchased by General Dynamics, and operated as their Convair Division for most of its corporate history. Convair is best known for its military aircraft; it produced aircraft such as the Convair B-36 Peacemaker and Convair B-58 Hustler strategic bombers, and the Convair F-102 Delta Dagger and Convair F-106 Delta Dart interceptors. It also manufactured the first Atlas rockets, including the rockets that were used for the crewed orbital flights of Project Mercury. The company's subsequent Atlas-Centaur design continued this success and derivatives of the design remain in use as of 2020. The company also entered the jet airliner business with its Convair 880 and Convair 990 designs. These were smaller than contemporary aircraft like th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Velocity
Velocity is the directional speed of an object in motion as an indication of its rate of change in position as observed from a particular frame of reference and as measured by a particular standard of time (e.g. northbound). Velocity is a fundamental concept in kinematics, the branch of classical mechanics that describes the motion of bodies. Velocity is a physical vector quantity; both magnitude and direction are needed to define it. The scalar absolute value (magnitude) of velocity is called , being a coherent derived unit whose quantity is measured in the SI (metric system) as metres per second (m/s or m⋅s−1). For example, "5 metres per second" is a scalar, whereas "5 metres per second east" is a vector. If there is a change in speed, direction or both, then the object is said to be undergoing an ''acceleration''. Constant velocity vs acceleration To have a ''constant velocity'', an object must have a constant speed in a constant direction. Constant direction cons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat-seeking
Infrared homing is a passive weapon guidance system which uses the infrared (IR) light emission from a target to track and follow it seamlessly. Missiles which use infrared seeking are often referred to as "heat-seekers" since infrared is radiated strongly by hot bodies. Many objects such as people, vehicle engines and aircraft generate and emit heat and so are especially visible in the infrared wavelengths of light compared to objects in the background. Infrared seekers are passive devices, which, unlike radar, provide no indication that they are tracking a target. That makes them suitable for sneak attacks during visual encounters or over longer ranges when they are used with a forward looking infrared or similar cuing system. Heat-seekers are extremely effective: 90% of all United States air combat losses over the past 25 years have been caused by infrared-homing missiles. They are, however, subject to a number of simple countermeasures, most notably by dropping flares beh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trent 700
The Rolls-Royce Trent 700 is a high-bypass turbofan produced by Rolls-Royce plc to power the Airbus A330. Rolls-Royce was studying a RB211 development for the A330 at its launch in June 1987. It was first selected by Cathay Pacific in April 1989, first ran in summer 1992, was certified in January 1994 and was put into service on 24 March 1995. Keeping the characteristic three-shaft architecture of the RB211, it is the first variant of the Trent family. With its fan for a 5:1 bypass ratio, it produces 300.3 to 316.3 kN (67,500-71,100 lbf) of thrust and reach an overall pressure ratio of 36:1. It competes with the General Electric CF6-80E1 and the PW4000 to power the A330. Development When Airbus launched its A330 twin-jet in June 1987, its only engine options included the General Electric CF6-80C2 and the Pratt & Whitney PW4000. Rolls-Royce was studying whether to launch a RB211-700, development of the RB211 for the A330, the long-range Boeing 767 and McDonnell Douglas MD- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airbus A330
The Airbus A330 is a wide-body aircraft developed and produced by Airbus. Airbus conceived several derivatives of the A300, its first airliner in the mid-1970s. Then the company began development on the A330 twinjet in parallel with the A340 quadjet and launched both designs with their first orders in June 1987. The A330-300, the first variant, took its maiden flight in November 1992 and entered service with Air Inter in January 1994. The slightly shorter A330-200 variant followed in 1998. The A330 shares its airframe with the early A340 variants, having two main landing gear legs instead of three, lower weights, and slightly different lengths. Both airliners have fly-by-wire controls as well as a similar glass cockpit to increase the commonality. The A330 was Airbus's first airliner to offer a choice of three engines: the General Electric CF6, Pratt & Whitney PW4000, or the Rolls-Royce Trent 700. The A330-300 has a range of 11,750 km or 6,350 nmi with 277 passen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PW4000
The Pratt & Whitney PW4000 is a family of dual-spool, axial-flow, high-bypass turbofan aircraft engines produced by Pratt & Whitney as the successor to the JT9D. It was first run in April 1984, was FAA certified in July 1986, and was introduced in June 1987. With thrust ranging from , it is used on many wide-body aircraft. Development The 52,000-62,000 lbf (230-275 kN), -fan PW4000 made its first run in April 1984, was FAA certified in July 1986, and was introduced in June 1987. It powers the Airbus A300-600 and Airbus A310-300, Boeing 747-400 and 767-200/300, and McDonnell Douglas MD-11 widebodies. Development of the , -fan version began in December 1991 for the Airbus A330, was FAA certified in August 1993, and made its first flight two months later. It received 90min Extended-range Twin-engine Operations (ETOPS) approval at introduction in December 1994, and 180min ETOPS approval in July 1995. In January 2000, it was the A330 market leader with more than hal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AH-64 Apache (Belgium) Radom - Panoramio
The Boeing AH-64 Apache () is an American twin-turboshaft attack helicopter with a tailwheel-type landing gear arrangement and a tandem cockpit for a crew of two. It features a nose-mounted sensor suite for target acquisition and night vision systems. It is armed with a M230 chain gun carried between the main landing gear, under the aircraft's forward fuselage, and four hardpoints mounted on stub-wing pylons for carrying armament and stores, typically a mixture of AGM-114 Hellfire missiles and Hydra 70 rocket pods. The AH-64 has significant systems redundancy to improve combat survivability. The Apache began as the ''Model 77'' developed by Hughes Helicopters for the United States Army's Advanced Attack Helicopter program to replace the AH-1 Cobra. The prototype YAH-64 was first flown on 30 September 1975. The U.S. Army selected the YAH-64 over the Bell YAH-63 in 1976, and later approved full production in 1982. After purchasing Hughes Helicopters in 1984, McDonnell Dougl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shear (fluid)
Shear stress, often denoted by (Greek: tau), is the component of stress coplanar with a material cross section. It arises from the shear force, the component of force vector parallel to the material cross section. ''Normal stress'', on the other hand, arises from the force vector component perpendicular to the material cross section on which it acts. General shear stress The formula to calculate average shear stress is force per unit area.: : \tau = , where: : = the shear stress; : = the force applied; : = the cross-sectional area of material with area parallel to the applied force vector. Other forms Wall shear stress Wall shear stress expresses the retarding force (per unit area) from a wall in the layers of a fluid flowing next to the wall. It is defined as: \tau_w:=\mu\left(\frac\right)_ Where \mu is the dynamic viscosity, u the flow velocity and y the distance from the wall. It is used, for example, in the description of arterial blood flow in which case which there ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
