Prediction of minimum water amount to stop thermal decomposition of forest fuel

Abstract

Presented are results of experimental studies of the heat transfer processes in suppression of thermal decomposition of typical forest fuels (FFs) (spruce needles, birch leaves, aspen twigs, or amixture thereof) due to the effect of aerosol water flow (drop radii: 0.01–0.12 mm; concentration: 3.8 · 10−5 m3 drop/m3 of gas). The experiments have been carried out with FF samples in the form of cylinders of a thickness of 40–100 mm and a diameter of 20–150 mm. The times required to stop the thermal decomposition of FF have been found, as well as amounts of water necessary to lower in a given time the temperature in a layer of material to the point of decomposition beginning. A dimensionless complex has been derived for prediction of water spraying parameters (amount and time of supply) that ensure sustainable termination of FF decomposition within a specified time interval.