MATHEMATICAL MODELING OF THE PROCESS OF FINE WATER MIST GENERATION BY SHOCK WAVES

Abstract

The conducted studies made it possible to identify the features of the process of fine water mist generation from the nozzle of a fire-extinguishing system under the action of shock waves and to sub-stantiate a mathematical model describing this process. Mathematical modeling was carried out using specialized simulation software based on the Volume of Fluid model. According to the results, the gen-eration of fine-dispersed water at the outlet of the fire-extinguishing nozzle under the influence of shock waves occurs within 1.13–1.73 ms, followed by a transition to steady-state atomization and dispersion within 2.02–2.41 ms. At 5.11–5.24 ms, the process terminates due to the depletion of water in the noz-zle. The most intense atomization was recorded at 1.73 ms, while the maximum spread of the water mist cloud occurred at 2.02 ms, defining the key stages of generation and process efficiency. The main parameters of water mist generation and delivery were determined, including the total volume, number of droplets, and density within the computational domain. The mist cloud was found to have a cylindri-cal shape with a water volume of 1.37 L(1.37×10-3 m3), and the average water density in the air-water flow was 0.343 kg/ m3. For water droplets of various dispersities, their main parameters were deter-mined. Thus, for droplets with a diameter of 5 μm, the volume of a single droplet is 6.54×10-17 m3, the total number of droplets is 7.2 million, and the droplet density within the fine water mist is 5.26×109 drops/m3. For droplets with a diameter of 50 μm, these parameters are 6.54×10-14 m3, 7.2 thousand, and 5.26×106 drops/m3, respectively; while for droplets of 100 μm, the corresponding values are 5.24×10-13 m3, 900, and 6.57×105 drops/m3. Mathematical modeling made it possible to investigate the process of fine water mist generation by the fire-extinguishing system under the influence of shock waves. The obtained parameters of fine-dispersed water determine the potential for its application in extinguishing fires of various classes, including under conditions of armed aggression.