what's difference between flame blow off and flame blow out???? plz help
Hello Mohamed,
"Blow off" is when the flow speed is so high, the flame cannot be stabilised (kept at a fixed location), and so you can watch the flame propagate downstream and eventually extinguish.
I haven't used "blow out" in a technical sense, but colloquially you "blow out a candle". I would describe this phenomenon as a very high flow speed that quenches the flame, so that it extinguishes at that location.
For "blow off", there is some flow to sustain the flame and the cause of the blow off is additional (but not excessive) speed in the same direction so that the flame can continue to burn as it moves because there is a combustible mixture. For "blow out", there is an enormous speed of flow, coming from any direction, which quenches the flame immediately because the temperature is quickly reduced and the mixture becomes excessively lean (normally) or excessively rich, so that there is no longer a combustible mixture.
Regards,
Andrew
Hello Mohamed. According to Dr Turns there is no difference between the terms. A brief explanation can be found on his book An Introduction to Combustion: Concepts and Application.
Hello Mohammed,
'Blow off' is the term used when flame extinguishes from the lifted condition. it occurs when the flow velocity is much higher than the burning velocity at the flame base. On the other hand, the blowout term is used when the flame extinguishes directly the burner exit. It results due to high straining of the flame as a result of very high flow velocity.
Refer to the paper for more information: Transitions and blowoff of unconfined non-premixed swirling flame. R.Santhosh
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