TY - JOUR
TI - Movement of water drops in a forest fuel layer in the course of its thermal decomposition
AU - Volkov Roman S
AU - Kuznetsov Geniy Vladimirovich
AU - Strizhak Pavel A
JN - Thermal Science
PY - 2018
VL - 22
IS - 1
SP - 301
EP - 312
PT - Article
AB - In this paper, we conducted an experimental investigation on water droplets  gravitating in a layer of typical forest fuel (as illustrated by pine needle  litter) in the course of its thermal decomposition. We used a high-speed (200  fps) video recording system, Tema Automotive software with continuous  tracking of a moving object as well as a set of low-inertia (no more than 0.1  s) thermocouples. Similar experiments were performed at moderate temperatures  (below the onset temperature of forest fuel pyrolysis, i.e. about 300 K). Two  approaches were used: continuous tracking of a moving water droplet using  high-speed video recording; and registration of a droplet path using the  readings of thermocouples placed at different levels in a forest fuel (FF)  layer. We determined the typical depths of an FF layer that water droplets  reach with the initial volume of these droplets ranging from 90 to 900 μL.  The typical velocities of water droplets were calculated at different depths  of the FF layer. We also determined the share of the mass of water spent in  an FF layer on evaporation and cooling of the material down to the  temperatures below those of thermal decomposition. Finally, we identified the  physical processes influencing water droplets moving through the layers of  forest fuel heated up to the high temperatures similar to those of thermal  decomposition.