Application of Low-Frequency Acoustic Waves to Extinguish Flames on the Basis of Selected Experimental Attempts

Abstract

Featured Application For industrial-scale extinguishment, natural processes such as acoustic wave propagation can be used. As proven, a technology described in the article using modulated and unmodulated waves can be applied to extinguish flames, as well as to control them. The results presented in the article are limited to extinguishing candle flames, but in the long term, this technique can be used to extinguish flames (especially firebreaks) from various materials (Classes C and B). This inexpensive, versatile, and environmentally safe method can provide a supporting or additional means of fire protection, especially useful in the first stage of fire occurrence. This technique appears to be environmentally friendly (it does not leave stains and does not emit chemicals). Moreover, acoustic waves can be applied to reduce the intensity of smoke and harmful substances in the ambient air, the presence of which is the result of fires (future plans).Abstract Due to the consequences of fires, new and environmentally friendly firefighting techniques are constantly being sought. There are many methods of extinguishing flames around the world. One of them is a technique that uses acoustic waves for extinguishing, which can be seen as repeated sequences of molecular compression and dilation (acoustic waves transfer energy due to the movements of molecules and atoms). This research shows a new approach to the extinguishing of flames. In practice, the extinguishing capabilities of low-frequency modulated and unmodulated acoustic waves were tested on a laboratory station, the main component of which was a high-powered acoustic extinguisher (the nominal power was equal to 1700 W). A B&C 21DS115 woofer was applied as a sound source. A Rigol DG4102 and a Proel HPX2800 were used as an acoustic generator with a modulator and as a power amplifier, respectively. In this paper, the presented results are limited to extinguishing candle flames. The tests made it clear that flames can be extinguished using properly generated and directed acoustic waves. As the results indicate, it becomes possible to effectively extinguish flames with both low-frequency modulated and unmodulated acoustic waves, which brings many benefits.