SOME TEMPERATURE CHARACTERISTICS SUB-LAYER AEROSOL EXTINGUISHING OF ALCOHOLS
Authors: Balanyuk V. , Kozyar N. , Kravchenko A. 
Published: January 2021

Problem Statement: Nowadays, the process of sublayer aerosol quenching has not been studied at all, and its basic parameters, such as changes in flame temperature, liquid surface layer, tank sides, and approximate time of alcohol quenching and quenching, are unknown. The purpose of the work is to determine the parameters of sublayer aerosol quenching - flame temperature, the surface layer of liquid, tank sides, and the impact on the efficiency of sublayer quenching of aerosols dispersion – as one of the main parameters characterizing the process of alcohol quenching. The scientific novelty of the work is that for the first time the parameters of sublayer aerosol quenching at different sizes of aerosol bubbles were determined and it was found that at smaller bubbles the surface layer temperature decreases to 15%, aerosol distribution on the liquid surface is more uniform and a heterogeneous system is formed, which contains both aerosol solid particles – K2CO3, KOH, KNSO3, NH4HCO3, gases – CO2, N2, H2O, alcohol vapors, and the alcohol itself in the vapor and liquid phases. The main results of the study: The paper describes the developed installation and methodology for determining the parameters of sublayer aerosol quenching at different stages of the aerosol release process. The values of the flame temperature reduction and its behavior when the aerosol enters the flame are established. The established values are plotted and it is determined that when the aerosol enters the flame, the flame temperature begins to decrease actively and in 40 seconds reaches about 600 degrees Celsium. It was also found that the flame turns orange, which indicates that the combustion zone is the thermal dissociation of potassium salts, the flame size decreases, which indicates a decrease in the amount of alcohol vapor entering the combustion zone. The rate of cooling the sides at the exit of the aerosol from different-sized holes was also determined and it was found that the amount of cooling of the tank side is slightly higher at smaller hole diameters with a more uniform distribution of the aerosol on the surface. The range of reduction of liquid and board temperatures for each of the alcohols is less than the boiling point by 30-40 degrees Celsium. The decrease in temperature occurs at approximately the same rate and slows down until the end of the aerosol release. Analysis of the experimental results showed that the action of fire-extinguishing aerosol when it comes to the surface leads to intensive alcohol cooling due to bubbling of the aerosol through the alcohol layer, with active mixing of alcohol layers and the rise of cold liquids to the surface. This phenomenon leads to further cooling of burning surface of the liquid, which can have a temperature of 60 degrees Celsium to 97 degrees Celsium, as well as the sides of the tank as a result of alcohol on them and its intense evaporation. The result is the establishment of the parameters of the sublayer aerosol quenching – the temperature of the liquid surface, the temperature of the sides of the tank, the rate of aerosol to the surface, and the flame temperature when the aerosol enters the combustion zone.