Extinguishment of N-heptane Diffusion Flames with the Shock Wave
Journal Title: Safety & Fire Technology - Year 2016, Vol 42, Issue 42
Abstract
Objective: 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. Methods: 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.
Authors and Affiliations
канд. техн. наук. В. М. Баланюк / V. M. Balanyuk , Ph. D.
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