Numerical Simulation Of Fire Suppression Of Water Mist System

Water mist vaporizes quickly in fire, and can extinguish the fire efficiently and rapidly with its cooling and chocking effects. Compared with traditional fire-fighting techniques, water mist suppression owns many advantages such as low water consumption and no pollution, and it has become an ideal alternative for halon fire extinguishing agents.Traditional fire study lies on full-scale experiments to obtain the key parameters, so it's limited by its low economical efficiency and high measuring difficulty. On the other hand, computer-based numerical simulation can easily get smoke concentration, temperature, air flow rate and other relevant data within a 3D space. And it also has advantages like small investment, short period, and useful guidance for actual designs.The main research of this thesis are the applications of FDS on combustion of constant power fire, alcohol fire and gasoline fire, as well as on the water mist fire suppression process. Here summarize the main work and conclusions.1) A model of fire suppression room has been built with FDS, with spray devices, a measure system (for temperature, smoke, air flow rate, etc.), and a fire source which can be either constant power fire, alcohol fire or gasoline fire.2) The combustion processes of the three kinds fire within a certain room have been simulated, to examine the fire source power and the space distribution of temperature and smoke. The process of suppressions on the three kinds fire with water mist system also got simulated, to compare the suppress efficiencies of different fire powers, droplet diameters, nozzle flow rates, vertical distances from nozzle to fire source, and ventilation conditions. And the result showed that better suppress efficiency can be got when the droplet diameter is 50μm or 100μm, the nozzle flow rate is 5L/min, the vertical distance is 1.6m or 1.8m, and the ventilation is bad.3) A water mist suppression system has been designed with reference to current design standards and simulation models of such system. One 3D building software has been utilized to build models of the system and the fire suppression room, and the nozzles and thermocouples have been deliberately placed. Simulink/RTW has been used to build a data acquisition system. And the experiment processes have been set down with reference to current standards, which lay a foundation for future experimental study of water mist suppression.