One or the other has to (IMHO) wick more fuel from the reservoir.
I find it hard to believe that butane escapes the nozzle at the same rate whether or not the fuel is being burned or not. My money is on burning fuel leeching, or at least drawing, fuel faster from it’s source than gas just escaping from a nozzle.
I’m sure some “gassy” doper can give me the goods.
I fail to see why; in either case the gas is escaping from a reservoir of equal pressure, to the free atmosphere at an equal pressure, through an aperture of equal diameter. If it was actually being “wicked” as in a kerosene lamp, then certainly I can see this holding true, but not with a regular Bic.
I agree with Nanoda, one caveat being that if the lighter were lit for a long time, it would heat the resevoir and create more pressure in the lighter.
If you look at the flame, it’s a millimeter or two away from the nozzle due to the fact butane must mix with air before it will burn.
The heat could expand the aperture also. The cooling effect of the gas would serve to close the apertue.
On the other side the combustion is creating a small high pressure reagon at the point of exit of the gas, so the gas is not exiting at the same pressure.
A totally Wag:
At 1st the rate of the non ignited gas would be slightly higher due to the back pressure on the ignited one. The non ingited apature would cool faster due to the expanding gas (leaving at a higher rate rate and not being warmed by the combustion), so the ignighted one would start to come back and overtake it in terms of gas usage. Then the ignighted one would start warming the fuel and pull away much greater.
So, burning butane empties the reservoir faster? Technically.
I think it’s better to say it empties faster when warm, and it’s more likely to be warm when close to a flame.