Temperatures of flames

[abbrev]

I have read conflicting statements on where the flame of a jet torch lighter is hottest and could not find a conclusive explanation. On one hand I read that the blue part is the hottest part as it contains most compact heat on another forum I read that the hottest part is in front of the blue part because the blue is unburned fuel. Another guy said the hottest sweet spot would actually be in front and above or below the flame because compressed air cools it, which also would make sense.

However, my head is spinning and I don't know what to make of it. By any chance does someone have a diagram of a butane jet torch lighter type flame handy indicating the temp zones? It has to be on Google but I couldn't find it, only pages and pages of ads for jet lighters...

 

[OF]

I have read conflicting statements on where the flame of a jet torch lighter is hottest and could not find a conclusive explanation. On one hand I read that the blue part is the hottest part as it contains most compact heat on another forum I read that the hottest part is in front of the blue part because the blue is unburned fuel. Another guy said the hottest sweet spot would actually be in front and above or below the flame because compressed air cools it, which also would make sense.

However, my head is spinning and I don't know what to make of it. By any chance does someone have a diagram of a butane jet torch lighter type flame handy indicating the temp zones? It has to be on Google but I couldn't find it, only pages and pages of ads for jet lighters...

While confusing (and more so for all the good sounding theories out there), this is actually a very easy one for you to test for yourself. Get a fine steel wire several inches long and hold it through the flame. You can see it glow where it's hottest.

You'll note that close in, it glows on the ends in the flame, but not the center. This is because the center of the cone is made of cold air and fuel that have not burned. Combustion is taking place at the interface between the inner and outer cone, as you can clearly see as you raise the wire up in the flame. The two glowing parts get brighter as they come together. Since it's basically a two stage combustion process (most of the heat coming from the Carbon to CO2 part, not the Hydrogen to water (the reason Acetylene burns hotter, less Hydrogen)) maximum heat is usually found just in front of the inner cone. It does vary some, so get some wire and prove what's happening with yours.

Iron or stainless wire only, not copper. A single strand from stranded 'picture hanging wire' is ideal.

OF

 

[t-dub]

OF, sometimes pictures can help. Although this illustration is for a Bunsen burner flame, does it illustrate the basic "flame composition" you were trying to describe?

Edit: This might be better:

 

[OF]

OF, sometimes pictures can help. Although this illustration is for a Bunsen burner flame, does it illustrate the basic "flame composition" you were trying to describe?

Yup, it's a good general case picture for sure (but I think there were some of those already?), although it can vary some. The point I was hoping to make is it's easy and a much better idea to actually test the flame he intends to use. The visual indication of the heat as it's produced is is conclusive and likely not soon forgotten.

Thanks for the references.

OF

 

[SD_haze]