時間：2011-03-11 23:11來源：藍天飛行翻譯 作者：admin 點擊：次
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Since much of the air passing through a gas turbine engine is used only for cooling, it still contains a great deal of oxygen. Fuel is sprayed into the hot, oxygen-rich exhaust in the afterburner, where it burns and produces additional thrust. Afterburners, called reheaters in the United Kingdom, use a large amount of fuel, but the extra thrust they produce makes them efficient for high-performance aircraft. afterfiring (turbine engine). Fire that continues in the combustor after the engine is shut down. Afterfiring is normally caused by a malfunctioning manifold drain valve. afterfiring (reciprocating engines). A condition that can exist in a reciprocating engine when an excessive amount of fuel is taken into the cylinders. Some of this fuel is still burning when it is forced out of the cylinders, and it continues to burn in the exhaust system. Afterfiring is sometimes called torching. afterglow (cathode-ray tube). The light, or glow, remaining on the phosphorescent screen of a cathode-ray tube after the electron beam passes. after top center (reciprocating engine piston position). The position of the piston in the cylinder of a reciprocating engine after the crankshaft, turning in its normal direction of rotation, has caused the piston to pass the top of its stroke and start back down. aft-fan engine. A turbofan engine with the fan constructed as an extension of some of the turbine blades, rather than as an extension of the compressor blades. This fan pulls large volumes of air around the outside of the gas generator portion of the engine. aft flap. The rearmost section of a triple-slotted, segmented wing flap. See triple-slotted flap. age hardening (aluminum alloy heat treatment). The process of increasing the strength and hardness of aluminum alloy after it has been solution heat-treated. Age hardening occurs at room temperature and continues for a period of several days until the metal reaches its full-hard state. aging. A change in the characteristics of a material that takes place over a period of time under specified environmental conditions. Aging may cause the physical condition of the material either to improve or to deteriorate. Certain aluminum alloys do not have their full strength when they are first removed from the quench bath after they have been heat-treated, but they gain this strength after a few days by the natural process of aging. agitate. To stir something or to shake it up to mix its components. Agitating a mixture of ice and water causes the water becomes uniformly cooled. AGL altitude. Altitude, expressed in feet measured above ground level. agonic line. An irregular imaginary line across the surface of the earth along which the magnetic and geographic poles are in alignment and along which there is no variation error. The term agonic comes from the two Greek words “a,” meaning no, and “gonic,” meaning angle. agricultural aircraft. Aircraft especially designed and built for use in agriculture. |
