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AIRCRAFT PROPULSION : RAMJET ENGINE

 Gas turbines are particularly suited for aircraft propulsion because they are light and compact and have a high power-to-weight ratio. Aircraft gas turbines operate on an open cycle called "Jet propulsion Cycle", as explained below . It can be of turbojet, turbofan or turboprop type.


RAMJET ENGINE : 


A particularly simple type of engine known as ramjet engine requires neither a compressor or a turbine. A sufficient pressure rise  is obtained by decelerating the high speed incoming air in the diffuser (ram effect) on being rammed against a barrier. For the ramjet to operate , the aircraft must already be in flight at a sufficiently great speed. The combustion products existing the combustor are expanded through a nozzle to produce the thrust.




In each of  the engines mentioned so far, combustion of  the fuel is supported by air brought into the engines from the atmosphere. For very high altitude flights and space travel, where this is no longer possible, rockets may be employed. In a rocket , both fuel and an oxidizer ( such as a liquid oxygen ) are  carried on board of the craft. High pressure combustion gases are expanded in a nozzle. The gases leave the rocket at very high velocities, producing the thrust to propel the rocket.    

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