If you burn the gas from a gas bottle, why does the flame not propagate into the bottle?

Question

Is it because of the exit velocity of the gas?

In: Engineering

Answer 1

The flame needs both oxygen and fuel to burn. The bottle only contains gas (fuel) and the pressurized gas moving outwards prevents air from moving in the bottle and mixing with it. So, the flame only burns outside where the gas mixes with surrounding air.