Science Fair Project Encyclopedia
For other uses of afterburner, see Afterburner (disambiguation).
The jet engine afterburner is an extended exhaust section containing extra fuel injector nozzles. When the afterburner is turned on, fuel is injected and ignites immediately due to the high temperature of the exhaust gases. This combustion results in a very large release of hot exhaust, which expands and produces extra engine thrust.
Due to their high fuel consumption, afterburners are not used for extended periods. Thus, they are only used when it is important to have as much thrust as possible. This includes takeoffs from short runways (as on an aircraft carrier) and air combat situations.
One should note that since the exhaust gas already has reduced oxygen due to previous combustion, and since the fuel is not burning in a highly compressed air column, it is quite inefficient. Afterburners do produce markedly enhanced thrust as well as (typically) a very large, impressive flame at the back of the engine.
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