International Scientific Journal

Thermal Science - Online First

online first only

Movement of water drops in a forest fuel layer in the course of its thermal decomposition

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.
PAPER REVISED: 2017-04-01
PAPER ACCEPTED: 2017-04-19
  1. Calkin, D.E., Stonesifer, C.S., Thompson, M.P., McHugh, C.W., Large Airtanker Use and Outcomes in Suppressing Wildland Fires in the United States, International Journal of Wildland Fire, 23 (2014), pp. 259-271.
  2. Konishi, T., Kikugawa, H., Iwata, Y., Koseki, H., Sagae, K., Ito, A., Kato, K., Aerial Firefighting against Urban Fire: Mock-up House Experiments of Fire Suppression by Helicopters, Fire Safety Journal, 43 (2008), pp. 363-375.
  3. Thompson, M.P., Calkin, D.E., Herynk, J., McHugh, C.W., Short, K.C., Airtankers and Wildfire Management in the US Forest Service: Examining Data Availability and Exploring Usage and Cost Trends, International Journal of Wildland Fire, 22 (2012), pp. 223-233.
  4. Korobeinichev, O.P., Shmakov, A.G., Shvartsberg, V.M., Chernov, A.A., Yakimov, S.A., Koutsenogii, K.P., Makarov, V.I., Fire Suppression by Low-Volatile Chemically Active Fire Suppressants Using Aerosol Technology, Fire Safety Journal, 51 (2012), pp. 102-109.
  5. Dorrer, G.A., Mathematical Models of Forest Fire Dynamics. Moscow: Forest Industry. 1979. 160 p.
  6. Konev, E.V., Combustion Fundamentals for Plant Materials. Nauka, Novosibirsk 1977. 239 p.
  7. Janiszewski, J., Measurement Procedure of Ring Motion with the Use of High Speed Camera during Electromagnetic Expansion, Metrology and Measurement Systems, 19 (2012), 2, pp. 797-804.
  8. Janiszewski, J., Ductility of Selected Metals under Electromagnetic Ring Test Loading Conditions, International Journal of Solids and Structures, 49 (2012), 7-8, pp. 1001-1008.
  9. Vysokomornaya, O.V., Kuznetsov, G.V., Strizhak, P.A., Experimental Investigation of Atomized Water Droplet Initial Parameters Influence on Evaporation Intensity in Flaming Combustion Zone, Fire Safety Journal, 70 (2014), pp. 61-70.
  10. Glushkov, D.O., Kuznetsov, G.V., Strizhak, P.A., Volkov, R.S., Experimental Investigation of Evaporation Enhancement for Water Droplet Containing Solid Particles in Flaming Combustion Area, Thermal Science, 20 (2016), 1, pp. 131-141.
  11. Grishin, A.M., Sinitsyn, S.P., Akimova, I.V., Comparative Analysis of the Thermokinetic Constants for Drying and Pyrolyzing Forest Fuels, Combustion, Explosion and Shock Waves, 27 (1991), pp. 663-669.
  12. Lautenberger, C.H., Fernandez-Pello, C.A., A Model for the Oxidative Pyrolysis of Wood, Combustion and Flame, 156 (2009), pp. 1503-1513.
  13. Korobeinichev, O.P., Shmakov, A.G., Chernov, A.A., Bolshova, T.A., Shvartsberg, V.M., Kutsenogii, K.P., Makarov, V.I., Fire Suppression by Aerosols of Aqueous Solutions of Salts, Combustion, Explosion, and Shock Waves, 46 (2010), 1, pp. 16-20.
  14. Morandini F., Simeoni A., Santoni P.A., Balbia J.H., A Model for the Spread of Fire across a Fuel Bed Incorporating the Effects of Wind and Slope, Combust. Sci. Technol., 177 (2005), pp. 1381-1418.
  15. Tihay V., Morandini F., Santoni P.A., Perez-Ramirez Y., Barboni T., Combustion of Forest Litters under Slope Conditions: Burning Rate, Heat Release Rate, Convective and Radiant Fractions for Different Loads, Combust. Flame, 161 (2014), pp. 3237-3248.