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

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Discussion Overview

The discussion centers around the phenomenon of an audible pop and burst of flame that occurs when shutting off a propane grill. Participants explore the underlying causes of this occurrence, its implications on flame characteristics, and potential adjustments to the grill's operation.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested, Experimental/applied

Main Points Raised

  • One participant describes the pop as a result of cooler, denser air rushing in to replace the flame, which may complete the combustion of propane in an oxygen-depleted area.
  • Another participant notes that the flame extends significantly out of the grill, suggesting the possibility of a rich flame with unburned fuel, indicated by a yellowish color rather than a solid blue.
  • A different viewpoint suggests that the density and pressure of propane can displace air in the burner head, recommending a slow throttling of propane to observe changes in flame behavior.
  • One participant expresses curiosity about the potential for a more vigorous flame to lead to more economical fuel consumption if maintained.

Areas of Agreement / Disagreement

Participants present multiple competing views regarding the causes and implications of the pop and flame, with no consensus reached on the underlying mechanisms or the best practices for grill operation.

Contextual Notes

Participants mention various assumptions about flame characteristics, combustion processes, and the effects of air and propane interaction, but these assumptions remain unresolved.

Who May Find This Useful

Individuals interested in propane grill operation, combustion processes, and experimental approaches to flame management may find this discussion relevant.

mtworkowski@o
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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.
 
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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).
 
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.
 
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.
 
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
 

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