Reheat / afterburners
A question that occurred to me the other day...
An afterburner, as I understand it, is a fairly low-tech device whereby raw fuel is injected into the hot exhaust gases of a jet engine. The raw fuel burns, creating greatly increased thrust, although at the expense of greatly increased fuel burn rate.
I would have assumed that, for any well-designed and correctly-tuned internal combustion engine, the exhaust gases shouldn't contain any oxygen - the oxygen should all have been used up by ensuring that the fuel/air mix was correct to start with. However, if that was the case, the afterburner fuel wouldn't have anything to react with.
What am I missing? Are the just engines leaned off when afterburner is selected, allowing some oxygen to make it through?
Cheers for any pointers...