INVESTIGATION OF THE RATE OF HEAT RELEASE AND THE RATE OF MASS LOSS OF PINE NEEDLES IN A FIRE
Given the large number of processes and factors that occur during forest fires, covering several orders of magnitude in spatial and temporal scales, approaches to modeling the spread of forest fires are an urgent task. For a detailed analysis of the fire, a complete screening of process is required. Experiment of pine needle configurations is presented in the article. The measurement of the rate of heat release and the rate of mass loss over time for a fire in laboratory conditions was carried out between flat and inclined configurations of pine needles at an angle of 20 °. The results of the research, allowed us to establish that the combustion quickly reaches a quasi-stationary state of horizontal location on the surface of pine needles with a heat release rate of almost 100 kJ/h and a mass loss rate maintained at 6 g/sec during the entire combustion. For the configuration of pine needles with a slope of 20°, the combustion process demonstrates extremely unstable characteristics, since the rates of heat and mass release do not reach constant values. Fire for tilted configurations, the heat release rate and the mass loss rate are at the maximum level, demonstrating a peak value corresponding to 300 kJ/h and 15 g/s, respectively, between 100 and 150 seconds after ignition. In the course of the research, it was found that the surface of the flame front increases over time when burning pine needles at an angle of inclination of 20 . The data obtained during the experiment allowed us to establish that the rate of fire propagation and the burning process on a flat area of woodlands and on slopes will be different. Fire this fact should be taken into account when developing fire extinguishing tactics in forests in order to increase the efficiency of the extinguishing process.