[Stoves] air for gazification

[AJH]

On Tue, 19 Jun 2007 21:49:17 +0200, Boll, Martin Dr. wrote:

>I intended to get to know some amount of air related to the cross-section of
>the burning-chamber (or grate) which makes a good gasification in a T-LUD.

I'm a bit rushed again Martin but the term you and Frank seem to be
searching for is "superficial velocity" and it is a measure of the
rate air reacts with the column of fuel whilst neglecting the space
taken up by the fuel, it's a term Tom Reed has used and with a bit of
luck he might explain it.

TLUD stoves have a very low superficial velocity whilst pyrolysing but
to burn out the char it needs to be increased (20 fold??) to turn the
device into an updraught gasifier, this off course would then subject
the stove body to over 1100C.
>
> 

>
>How about making a T-LUD burning chamber with different cross sections on
>top for begin (=strong upwarming /boiling) with bigger cross section and 
>
>in the lower part of the burning chamber a small cross-section then for the
>following lower heat output  (=simmering-time).


I don't know because I haven't tried it. It compromises one of the
chief attributes of the inverted down draught principle which is
behind tlud and that is the constant supply of a constant calorific
value offgas.

AJH