Smoldering wave propagation mechanism. II. Smoldering velocity and temperature in smoldering zone

Critical smoldering conditions were considered in [i]. Let us now consider data pertaining to the smoldering velocity. We should immediately emphasize that the characteristics of smoldering wave propagation along the free surface of the fuel (i.e., at the boundary with the gas) may differ considerably from those for smoldering from the end of a flat fuel and pressed on both sides by inert layers (or a cylindrical fuel bed in an inert shell). We will arbitrarily call systems of the first type "open" or "semi-open" (if the fuel bed is in contact with an inert substrate on one side), and we will call systems of the second type "closed". Accordingly, we will symbolize the smoldering velocity in the first case as w, and in the second as u.