Fuel, heat and oxygen makes fire. My guess is the flare up is the oxygen being sucked in towards the heat and fuel. And as I said, it’s a guess.
Throw a few gallons of diesel on there and get the party started!!!!!
(do not play with gasoline)
my guess as well, maybe because before the flare up the Oxygen available is normal, after the initial flare the air is heated and surrounding air would be less dense, so less Oxygen would be available. Not being a scientist, I really wouldn’t know, they probably don’t either, but I bet they could fill a book or two on the subject anyway.
That would be my guess, also all the fuel vapor will be consumed in a fraction of a second, leaving only the liquid fuel left to slowly vaporize and feed the flames.
Thanks for reminding me, oxygen and fuel are two different things! I have been mixing them up here. :(