[Stoves] Basics: about self-ignition-temperature/ flash-point-temperature

[Paul Anderson]

Martin,

I found your comments to  be very interesting and useful.

You wrote:
> And these thoughts lead to the questions about, how small/less-powered 
> a wood- or a wood-gas-stove can be constructed.
> Thoughts and solutions about the heat-loss by radiation will come into 
> compilation, as well as fuel size and shape.
>
I am VERY interested in the small stoves, and am working on them, as are 
several others.   Let's see what develops.

Paul

Doc  /  Dr TLUD  /  Prof. Paul S. Anderson, PhD
Email:  psanders at ilstu.edu
Skype: paultlud      Phone: +1-309-452-7072
Website:  www.drtlud.com

On 5/25/2014 3:43 PM, Boll, Martin Dr. wrote:
> There are a lot of burning principles we all think they are very 
> trivial, but I think, it is worth thinking/meditating about.
>
> The advantage is,they are well known, the disadvantage is, all of us 
> are not every time aware of the aspect they give, seen out of the most 
> different angles of view.
> Happily the stovers are a very inhomogenous community, so that the 
> personal angle of view differs a lot. And each other telling combined 
> gives a more "three-dimensional" view; -very happily!
>
>  My first attempt about:
> 1. Self-ignition temperature  ( further as: SIT)
>
> To get a sustaining burn, there must be _always_ a temperature above 
> the SIT of the fuel.
> By burning wood we have to deal first with the high SIT of woodgas and 
> then with the low SIT of charcoal.
> Therefore it is "hard" to start a wood/woodgas fire, but easy to 
> maintain a charcoal-glow.
>
> Appliance:
> -Starting a fire by friction is first making charcoal-dust, to have a 
> fuel with low SIT, so low that we can reach it by friction.
> We could never reach the SIT of/for woodgas by friction.
>
>
> 2. The flash-point-temperature: (further as: FPT)
>
> Appliance:
> - Starting fire with a spark (-high temperature-), we can use a very 
> fine "split" fuel as cotton-wool, or some wool-like seeds (Common 
> dandelion, Taraxacum officinale;
> Canadian Poplar, Populus Canadensis; Field thistle, Cirsium arvense ) 
> . That tends to be very similar to a gas-air cloud, which is above 
> burnable liquids, with low evaporation temperature.
>
>
> Different fuel; how to rise its flame temperature:
>
> Charcoal ( has low SIT): Simply blow cold air onto the charcoal, -even 
> excessively blow does work.
> Woodgas ( has high SIT ): Make a good gas-air-mixture, but avoid too 
> fast air-stream (blow-out)
>  even important ore more: Reduction of overflow air, pre-warming of 
> used air, ideally prewarmed to or near SIT.
> But the other advantage; woodgas has a low FPT, and can therefore be 
> lit/relit with a spark ( e.g. woodgas driven engines)
>
> All those thoughts are basics to help to succeed or fail in appliance, 
> and now worth to combine with the discussion, about turning-down-ratio 
> in progress.
> The very good reported turn-down experiments, are good examples of 
> applied basics.
>
> Because of the different SITs, we are aware of: It is more difficult, 
> to run a _very_ small woodgas-fire in comparison with an even-powered 
>  _very_ small charcoal-fire.
>
> And these thoughts lead to the questions about, how small/less-powered 
> a wood- or a wood-gas-stove can be constructed.
> Thoughts and solutions about the heat-loss by radiation will come into 
> compilation, as well as fuel size and shape.
>
> Interested to see your ideas and angles of view about in discussion, 
> to get a more "three-dimensional" view for all of us.
>
> Regards
> Martin
>
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