Abstract
Aim: To determine the effectiveness of extinguishing diffusion flames of n-heptane with a shock wave (SW). Establishing a possible mechanism of suppression of diffusion flame with a shock wave on n-heptane С7Н16 flame. Determination of the intensity of the shock wave, which leads to extinguishing n-heptane flame under a special camera.
Methodology: To determine the possibility for extinguishing the diffusion flame by a shock wave, which occurs during the explosion of a pyrotechnic charge, equipment that looked like a camera with volume of 0.5 m3 was installed. A surge generator was placed inside it and a crucible with n-heptane was located at a distance of 1.75 m. The pressure measurement at the front of the shock wave was conducted using BMP-180 pressure sensor for Arduino controllers. Visualization of the extinguishing process of the shock wave was carried out using Nikon 1 j4 camera with the possibility of obtaining frames at a speed of 1200 frames per second.
Results: This article presents as an experiment that the impact of a shock wave with front pressure of about 215 Pа in the chamber at a distance up to 2 meters on n-heptane flame, oleads to its suppression by tearing and defragmentation. Time periods, which confirm the effectiveness of fire-extinguishing of the shock wave, and the transition states of instability have been recorded on video at a frequency of 1200 frames per second. This way respective stages of the storyboard, time periods of flame instability at a pressure of 190 Pa SW, and extinguishing time capacity SW of 215 and 316 Pa were obtained.
Conclusions: Extinguishing diffusion flames of n-Heptane shock wave with a power equal to approximately 215 Pа created in the chamber at a distance of 2 meters were theoretically analyzed and experimentally proven to be highly effective e. Based on presented theoretical deliberations a possible mechanism of interaction of shock wave – flame was created. As a result of tearing of the flames, reduction of the following parameters takes place: concentration of the reactants in the combustion zone, pressure, introducing additional gaseous components into the combustion zone, and a sharp decrease in temperature of gasaround the flame. The proposed extinguishing method can guarantee efficient extinguishing of diffusion flames at the initial stage of a fire in hard to reach places and spaces with flammable liquids.
Keywords: fire, shock wave, fire extinguishing, fire suppression, diffusion flame
Type of article: original scientific article