Clean Burning with Metering and Mixing

Primary air usually controls the rate of reactions: How fast the solid biomass changes into wood gas.

Jets of primary air into the charcoal beneath the biomass add mixing while raising temperatures.

Secondary air jets into the side of the flame can also supply needed mixing but tend to lower temperatures.

Metering the gas supply into the tuned combustion chamber is important!

Too much wood gas can easily overcome the ability of even a well-tuned combustion chamber to achieve close-to-complete combustion. 

You can’t pour too much gas into a carburetor!