A long tube located between the turbine and the nozzle of a jet
engine into which additional fuel can be injected and burned to provide
a significant boost in thrust for short periods.
Afterburning (or reheat) is a method of augmenting the basic thrust of an
engine to improve the aircraft takeoff, climb, and (for military aircraft)
combat performance. In an afterburner, fuel is introduced between the engine
turbine and the jet pipe propelling nozzle, utilizing the unburned oxygen
in the exhaust gas to support combustion. The increase in the temperature
of the exhaust gas increases the velocity of the jet leaving the propelling
nozzle and therefore increases the engine thrust. This increased thrust
could be obtained through use of a larger engine but at the cost of a significant
additional weight to the aircraft.
Afterburners can be fitted to both turbojet and turbofan engines. The disadvantage
of them is that they greatly increase fuel consumption during the periods
they are working.