Abstract
In this experiment, the wood boards were heated on the electric furnace. The distribution of the air temperature near the surface of board was measured by thermocouples with electromagnetic oscillograph and the processes of smoke and flame-formation at the ignition were observed by the methods of light absorption, ion probe and eye sight.
The important results are the followings :
(1) The air temperature near the surface of board is slightly raised before ignition by slow oxidation of combustible decomposition products.
(2) The flame starts at the surface of wood board and propagates away from the surface. But the flame at the surface can hardly be seen with naked eyes.
(3) The smoke formed by the thermal decomposition of wood, contains only liquid particles made from various hydrocarbons but no solid ones.
(4) The components of combustible gases which play the important role at the ignition of wood are, contrary to expectation, inflammable liquid vapours of higher hydrocarbon, rather than combustible gases such as CO and H2.
