This question already has an answer here:
In addition to my previous question, I am mainly concerned with burning all the fuel.
Why isn't the combustion process using all of the Oxygen in the air? Is it because other gases are in the way and it isn't in the right place to help the reaction?
Are engineers limiting the amount of fuel into the process because they know some of the Oxygen won't be available for combustion due to its proximity(lack thereof) to the fuel?
How much fuel remains un-burnt in a modern jet engine? I thought that an after-burner was meant to use the fuel that somehow got through the whole process without combusting?
Wouldn't using pure O2 allow for a complete fuel burn? I do get that the added weight may not make it worthwhile since we need to weigh the value of complete burn against other non-monetary concerns(like pollution).
Finally, I assume the 2000-2500 degree C temp mentioned (in this answer) in the last post is to actually burn Oxygen. Although I know Oxygen is not flammable, I am sure everything does burn at some point. I do not want to actually burn the Oxygen.