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8th Thermal and Fluids Engineering Conference (TFEC)
March, 26-29, 2023, College Park, MD, USA

Development of The Bombardier Beetle Fire Extinguisher: CFD Model Investigation

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DOI: 10.1615/TFEC2023.num.045958

Abstract

By creating a fire extinguisher that mimics the defense mechanism of the Bombardier Beetle, many of the downfalls of modern fire extinguisher can be corrected. When threatened, the Bombardier Beetle can facilitate a chemical reaction in its abdomen that builds pressure, eventually releasing the reactants at high velocities, high frequencies, and for long distances. This mechanism can be replicated in a fire extinguisher by vaporizing water in a pressure chamber. This would allow for fires to be fought from a safer distance, with a safer working fluid, and more effectively. To examine this effect, multiphase flow was simulated through an experimental chamber geometry using Computational Fluid Dynamics (CFD). With a very basic model, it was found that the water mixture was sufficiently above vaporization temperature, the vapor had a maximum volume fraction above 50%, and the outlet velocity was about 50% higher than the inlet velocity. These results prove the viability of this mechanism in firefighting applications. In pursuit of a more accurate model, timestep size, mesh resolution, and model settings were modified to see their effects, with the latter two items yielding significant changes. By proving the feasibility of this technique, lives and resources can be preserved and improved not only by its use in fire extinguishers, but also in sprinkler systems, fuel injectors, pharmaceutical sprays, and many other fields of study.