航空发动机术语.docx

Acceleration lag --in the turbine engine, delay between the time instant power is requested and when power is available. The time it takes the engine to accelerate and give the required power increase.Aerodynamic drag --force which thrust must overcome to move an aircraft forward. Design can lesson aerodynamic drag through streamlining. Drag increases with increased speed.Airbleed actuator --device that operates the interstage bleed system, to improve compressor acceleration characteristics by unloading small amounts of compressed air .Air density--total mass of air per given volume, the weight of a given volume of air . Air is denser at lower altitude, at lower temperature, and lower humidity.Airfoil profile --outline of an airfoil section.Airfoil section --cross section of an airfoil parallel to a specific reference plane.Air-fuel ratio --Ideal mixture of 15 parts of air to 1 part of fuel by weight; the mixture to be burned in the combustion chamber .Air inlet --large, smooth aluminum or magnesium duct at mouth of engine which conducts air into the compressor with minimum turbulence and restriction.Aluminum alloy --any of a variety of alloys formed by combining commercially pure aluminum withother metals or materials such as copper , silicon, manganese, magnesium, and zinc.These alloying agents maybe added singly or in combination to produce a metal with desired characteristics or strength, heat resistance, corrosion resistance, and the like. Both wrought-and cast-aluminum alloys are widely used in the manufacture of rotor blades and aircraft propellers.Ambient --condition of atmosphere existing around the engine, such as ambient pressure or temperature.Annular combustion chamber --two-part combustion chamber made up of an annular liner and a housing assembly.The compressed air goes into a ring-shaped space formed by the annular liner around the turbine shaft rather than into individual combustion chambers. The space between the outer liner wall and the housing assembly allows the flow of cooling air . Used with axial-flow and dual compressors.Annular reverse-flow engine --type of gas turbine engine most commonly used in Army aircraft. Airflow direction is reversed in the combustion area.Anti-icing system --device that supplies hot air under pressure to prevent icing of the inlet housing areas and inlet guide vanes. Hot scavenged oil is also circulated through internalpassages in the walls and struts.Army Spectrometric Oil Analysis Program 〔ASOAP〕 --periodic oil analysis for microscopic metal particles. This takes place at an oil analysis laboratory.Atmospheric pressure --barometric pressure exerted by the atmosphere as a result of gravitational attraction above the point in question.Atomizer --nozzle that creates minute particles and accurately shaped spray of fuel suitable for rapid mixing and combustion.Axial-flow compressor --one in which the air is compressed parallel to the axis of the engine. It is made up of a series of alternating rotor and stator vane stages.Bending --combination of tension and compression. The inside curve is under compression; the outside is under tension.Bleed system --device that unloads small amounts of air to relieve pressure.Boss --raised rim around a hole; e.g., axle hole in a wheel. Circular projection on a casting, usually serving as the seat for a bolt head or nut.Brayton cycle --constant pressure cycle, with four basic operations which it accomplishessimultaneously and continuously for an uninterrupted flow of power . The turbine engine operates on this cycle.Camber --the curvature of an airfoils surfaces from the chord line. It maybe positive, negative, or zero.Can-annular combustion chamber --one with characteristics of both the annular types. It has an outer shell and a number of individual cylindrical liners.Can combustion chamber --one made up of individual combustion chambers in which the air from the compressor enters each individual chamber through the adapter .Center of pressure --aerodynamic center of an airfoil; the point where all forces act.Centrifugal axial-flow compressor --combination of the centrifugal-flow and the axial-flow compressor . It usually consists of a five-or seven-stage axial-flow compressor and one centrifugal-flow compressor . Also called the dual compressor .Centrifugal-flow compressor --one with an impeller 〔rotor〕, stator , and compressor manifold. The rotor revolves athigh speed drawing air into the blades. Centrifugal force accelerates the air , and it moves through the stator and through the manifold.Centrifugal twisting movement --force that tends to streamline rotating blades with the plane of rotation.Choked nozzle --a nozzle whose flow rate has reached the speed of sound.Chord line --imag。