On Sunday 29 August 2010 15:05:55 Crispin Pemberton-Pigott wrote: > Dear Andrew > > I agree re pipe walls - they definitely run cooler with a vortex. You > mention the region of higher EA. Is that at the centre or the > periphery?
We measured at the top of a flue stack via a long pipe to lose temperature, there was no heat exchanger so all the flue heat was direct. The flue was 250mm and the vortex 1200mm so there was a lot of mixing going on after the combustion, which is why it was impossible to differentiate excess air that had passed through the combustion and dilution air that had passed up the outside of the vortex (because it was cool and more dense) and into the flue. When playing with smaller stoves (without the benefit of flue gas analyser) I formed the opinion that the heat exchange to a Kelly kettle must be inhibited by this effect. I experimented by putting some "fins" in the central tube to disrupt the vortex but never came to any conclusion. AJH _______________________________________________ Stoves mailing list [email protected] http://listserv.repp.org/mailman/listinfo/stoves_listserv.repp.org http://stoves.bioenergylists.org http://info.bioenergylists.org
