Venturi Gasifier Test.(Sept 18/97)
This shows the
rather bizzare arangement I used to do a boiling water test on the venturi
burner. It now has a 10cm diameter by 18cm tall cylindrical combustion
chamber opening at about 5cm directly under the pot. As is often the case,
it gave me some trouble getting started. So I lost a good deal of water
boiling time. Without the additional chimney it operates without the intensive
vortex or swirl action, however the flame was still fairly turbulent, thanks
to the bluf body. That is ofcourse while the pot was off and I could see
the flame. A thermo couple near the top of the combustion chamber gave
fairly consistant readings of 1450+/-25F, until the TC quit working. That
is 400F higher than the last test with the curvacious model. The CO2 was
often up around 17-19% with CO over the 2000ppm limit. Having no adjustment
on secondary air, I was forced to cut back on primary air. This brought
CO2 down to 11-13% and CO to 125-350ppm.(CO/CO2 of .002) At the higher
CO2 levels (and the pot removed) the flames extend out the top of the combustion
chamber. At the lower levels they did not. There was no visible smoke at
either time. In spite of early fumbleing it still managed to boil off 7.25
lbs of water with 7.75 lbs of wood. Certainly no efficiency breakthrough.
Probably a food burning breakthrough. On a positive note, CO was lower
than I expected.
This burner will soon go off to school where a 4th year engineering student at Queens will try to measure its performance and assist in its optimization. The way it looks now it certainly isn't "everymans" stove. I do however think that a practical low emissions burner for the charcoal maker is a possibility.
This picture shows
the veiw into the top. The pot is lifted out and over to reveal the 10cm
diameter combustion chamber. The orange hue is the flame. The metal cross
supports the pot and distributes the gasses.