The force has to be in either the same or the direction to the direction of motion for work to be done. what goes in the gap?

This is what i found “in a gas turbine engine, the combustor or combustion chamber is fed high pressure air by the compression system. early gas turbine engines used a single chamber known as a can type combustor. today three main configurations exist: can, annular and cannular (also referred to as can-annular tubo-annular).” i hope this you for what your looking for. can you plz mark me brainliest?