[Stoves] Request for help on TLUD operating data

[Ronal W. Larson]

List:

	I am trying to better understand TLUDs - for purposes of improving their performance.  This is to ask all char-making stove developers to report back, either on-list or off-list, on a fundamental characteristic of all TLUDs: the way performance changes over time.

	I have seen plots showing the weight of the stove-fuel combination; basically dropping relatively linearly as the pyrolysis front moves from top to bottom.  My question is on the word “relatively”.  Is that weight loss at the end dropping more (concave down) or less (concave up) rapidly than linearly?  

Stated as an equation, for a test run with a single fuel and a single primary air center the average linear equation could be:

	W(t)= Wo-A*t, with A = (W(t=tf)-W(t=o))/tf

but what I need is a quadratic form:

	W(t) = Wo - B*t + C*t^2

where B is certainly positive, but equal to A only if C is zero.

C can be either positive (concave up) or negative (concave downward).   The sign of C is the most important question I am asking - but even an approximate ratio C/B would be a big help.

	I only need a rough plot of the weight - then I can come up with the A,B, C constants.  I for sure need the starting and ending weights, and then at least a few other weights (and their times) near the end.  Knowing more on the stove would be helpful - especially the fuel can diameter.  The fuel  (sticks, chips, pellets, etc) is needed also.

Who can help?  (and leads to published material would be just as good.)

I will summarize and report - and can do this without using any names.

Ron