Specific Nature of Phlegmatizing Air-Heptan Mixture using Aerosol and Nitrogen Binary Mixture

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Specific Nature of Phlegmatizing Air-Heptan Mixture using Aerosol and Nitrogen Binary Mixture

Journal Title: Safety & Fire Technology - Year 2016, Vol 44, Issue 44

Abstract

Purpose: The purpose of the work is to determine the characteristics of phlegmatization of stoichiometric air-heptan mixture with aerosolnitrogen binary mixture, as well as to determine the concentration and combustion time of the combustible mixture in different ratios of the components of these mixtures. Methods: To determine the characteristics of n-heptan phlegmatization using aerosol-nitrogen binary mixtures, an installation was used of a thick-walled cylindrical glass vessel of 0.5 liter capacity with a powerful electric ignition source placed inside it. An aerosol-nitrogen mixtured was combined with an air-heptane mixture. Time-lapse shots of the explosion process were captured by Nikon 1 j4 camera which can capture 1200 frames per second. Results: The results of the experiments showed that the value of phlegmatization concentration of aerosol obtained on the basis of the mixture for aerosol formulation based on iditol for the stoichiometric mixture is 66 g/m3. Also obtained was the dependence between the concentration of the mixture of the phlegmatizer and the proportion of the content of its ingredients, taking into account the condition that a single concentration of the phlegmatizer (the aerosol-nitrogen mixture) is 44%. It was also discovered that the optimum ratio of the components of the mixture are as follows: aerosol – 20-35 g/m3, N2 – 15%-8%. Significant fire resistant efficacy of the binary mixture has been shown, which is meant to reduce the spread of the flame front over the whole volume of the combustible mixture, when the fireball dies before touching the walls of the cylinder. As a result of the conducted experiments, the synergistic interaction between components of the binary aerosol-nitrogen mixture was also confirmed, which is manifested by a sudden decrease in concentration of its components due to their combined action. The components of the mixture act both as heat phlegmatizers and chemical inhibitors. Shots were obtained of combustion processes resulting from explosion while adding aerosol-nitrogen binary mixtures to a stoichiometric binary mixture. The shots confirmed the phenomenon that fire reduced by a phlegmatizer while the concentration of aerosol and nitrogen is decreased three times, which ensures maintaining the oxygen concentration at a level suitable to maintain human life processes Conclusions: The paper presents the effect of reducing the spread of flames over the entire volume of the fuel mixture of heptane and air when the aerosol-nitrogen binary mixture was added. The effect is interesting from a practical point of view: in order to ensure fire safety and explosion protection of buildings (sites) where there are flammable gases, liquids and mixtures thereof. Practical application of the binary mixture for extinguishing and phlegmatization will result in reducing the scale of destruction due to limiting the spread of flames over the entire volume of the homogeneous fuel-air mixture.

Authors and Affiliations

V. M. Balanyuk

Keywords

EP ID EP363554
DOI 10.12845/bitp.44.4.2016.11
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