时间：2011-03-11 23:18来源：蓝天飞行翻译 作者：航空 点击：次
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reaction turbine. A type of turbine wheel turned by an aerodynamic force produced by the turbine blades. This force is similar to the lift produced by an aircraft wing. The blades of a reaction turbine are small airfoils mounted on the periphery of the turbine wheel in such a way that they form converging ducts that accelerate the hot gases passing through them. The high-velocity gas flowing over the reaction turbine blades produces a pressure difference between the top and bottom of the blade. This pressure difference produces a force which rotates the turbine wheel. reactive current (electrical current). Current flowing in an alternating current circuit that is not in phase with the voltage. reactive metal. A metal that reacts readily with oxygen to form an oxide. Aluminum and magnesium are both reactive metals. reactive power (electrical power). Wattless power in an alternating current circuit. Reactive power, the power consumed in the inductive and capacitive reactances in the circuit, is expressed in volt-amps reactive (VAR) or in kilovolt-amps reactive (KVAR). reactor(electrical circuit). A small coil installed in an alternating current circuit to furnish inductive reactance to cancel some of the capacitive reactance in the circuit. Reactors normally have very little resistance. “Read back” (air traffic control). A phrase used by ATC to mean “repeat my message back to me.” reader (microfiche system). An optical instrument used to read the information recorded on a microfiche. The microfiche is placed on the reader and moved around to position the correct image in front of the lens. The magnified image is projected onto a screen so the operator can read it. Some microfiche readers have a built-in printer that makes a hard copy of the projected image. This type of reader is called a reader-printer. real number. Numbers that include positive numbers, negative numbers, and zero. real power (electrical power). The power in an alternating current circuit that actually produces work. Real power (true power) is measured in watts and is the product of the circuit voltage and only the current in phase with this voltage. Real power can be found by multiplying the apparent power, the product of the total voltage and the total current, by the power factor, the percent of the total current in phase with the circuit voltage. ream (metalworking process). To enlarge a hole and smooth its sides. If a hole in a piece of metal is to be fitted with a close-tolerance part, it is usually drilled slightly undersize and cut to the correct diameter with a reamer. reamed fit. The fit of a shaft in a hole in which the hole is drilled undersize and cut with a reamer to the correct diameter. Reamed holes have smooth walls and a consistent diameter. reamer (metal-cutting tool). A cutting tool used to produce a smooth surface on the inside of a drilled hole. A reamer has several sharp cutting edges that cut away the rough surface left by the drill. |
