[Stoves] basics: Need different flame-speeds different mixture-procedures?

[Boll, Martin Dr.]

Dear all,

            reeding the the comments in the stoves-list, mentioning the
different flame speeds for H2 and woodgas  "a coin dropped in my mind".

There are "worlds" between the two different speeds.

-When you think of the draft of an open flame and a _real_  jet-blow, there
are also "worlds" between both in speeds too

So I come to basic thoughts for burning.

 

- For H2:  

There is good chance for retro-burning under normal conditions. There must
be a small nozzle hole, that this does not occur (in other words there must
be a point of _very high_ speed; faster then the flame speed (of 3 or 4
meters per second?)

 

- For wood-gas:

There is a good chance that the flame blows out itself, because the speed of
the outstreaming woodgas is too high.(Higher than 40cm per second?)

 

Conlusion: By woodgas the jet-speed must be _very_ different to fit
comfortely for a constant flame.

 

My question:

For H2 and other fast flame-speed stuff the jet is high and so there is a
good turbulence to mix gas and air.

For woodgas the gas-jet _must be_ slow for not blowing out. Therefore the
turbulence is _far less_.

 

Is this small turbulence big enough to make a comparable good mixture for
clean burn??

-Even by a normal kitchen gas-burner there is a gas-air premixture. Is this
premixture not more necessary by a slower jet-speed coming out of the
nozzle?

 

I guess:

 There must be at least a jet-blow against a baffle to get a stable flame.

_and_  there must be a _premixing_ before the balanced woodgas-air-mixture
passes through the nozzle _and_ then against a baffle to form a stable _and_
clean flame.

 

-What is the good range of speed for that? Or:

-What are good combinations for pressure difference  and diameter of the
nozzle, for a given gas/woodgas?

 -What is the good premixing ratio of woodgas and air? And has the premixing
air to be preheated? (For: quicker reaction time; and/or no precipitation
out of the woodgas?)

- Would a static-mixer be helpful te reach a good gas/air mixture with low
speed instead of a high-speed-jet? 

 

I hope not to ennoy you too much with simplicities.

 

Regards

 

Martin