What Causes the Pop and Flame When Shutting Off a Propane Grill?

[mtworkowski@o]

When a propane grill is shut off there is an audible pop and a burst of flame before it goes off. What is this and why does it happen. Also, is there more energy in this. It sounds and looks like there is.

 

[turbo]

A flame is rarified by its heat. Snuff it quickly and cooler denser air air pops into that space. That air has a fair amount of oxygen in it and it completes the burn of propane that was previously propagating through an oxygen-depleted zone (the flame).

 

[mtworkowski@o]

I should mention that the flame pops way out of the bottom of the grille. Perhaps 6 in. Does this mean that I'm running a rich flame full of unburnd fuel? The flame color is somewhat yellowish rather than being a solid blue like a natural gals flame like on a bunsen burner.

 

[turbo]

Propane is pretty dense, and it is under pressure, so it can displace air in the burner head. Try throttling back the propane slowly instead of just snapping it off and see what happens. Also, most grills feature a slotted collar with which you can vary the amount of air that the propane entrains as it enters the burner. Play with those, too. Experimentation will tell you a lot.

 

[mtworkowski@o]

Turbo-1
I'm not trying to solve the problem. It sounds like this is a much more vigorous flame and I was thinking that if it could be maintained that it would be at a more economical rate of fuel consumption. Could this be the case. thanks