Total flooding by temperature-activated water with inhibiting salts

Abstract

Purpose. Theoretical studies have established that one of the ways to increase the extinguishing efficiency of temperature-activated water (TAW) is by incorporating water-soluble inhibitory compounds into it. However, the process modeling of flooding fires of closed volumes by this medium and field experiments confirming the theoretical conclusions have not been carried out. The work aims at field research of flooding fires by TAW with inhibitory salts. For this purpose, the following tasks have been solved: – mathematical modeling of evaporation process of TAW droplets in a high-temperature environment; – field research of flooding by TAW with incorporation of inhibitory salts into it. Methods. Analysis and synthesis methods have been used to evaluate the available data. The theory of branched-chain combustion processes has been used to study flame inhibition processes. The objectivity of the theoretical dependencies found has been confirmed by the experimental method. Findings. The experiments have been carried out in a room with enclosing structures made of non-combustible materials. The room volume is 300 m3 with a total leakage parameter for a group of rooms of 0.012 m–1. To create TAW jets with inhibitory properties, a dosing device has been chosen that allows creating TAW jets with inhibitory salts mass concentration up to 18 %. In the first series of experiments extinguishment has been carried out by TAW without adding inhibitory salts. In the second series of experiments TAW jets have been used for extinguishing at the temperature of 140 °C of underheated water and a 10 % concentration of potassium hexacyanoferrate (II) to achieve inhibitory effect. The suppression time of fire seats by TAW jets with inhibitory substances dosing has turned out to be 1.5 times less, while the supply intensity has been 1.07 times higher. The method of total flooding effectiveness is confirmed by low specific volume consumption for extinguishing. The field research results correlate well with mathematical modeling results (the discrepancy is not more than 15 %), which allows verifying the model and using it in further research. Research application field. The obtained empirical dependences can be used to increase the efficiency of flame burning suppression in a closed volume. The research results will allow forming a theoretical basis for describing the mechanisms of blocking radical flame reactions by TAW with inhibitory properties. Conclusions. Based on experimentally established data and theoretical results, it can be argued that efficiency of total flooding by TAW jets when dosing inhibitory salts of appropriate concentrations increases by at least 1.5 times, and the combustion zone cooling efficiency by at least 1.6 times. The field research has allowed confirming the objectivity of theoretical dependencies found. The most effective distribution of TAW polydisperse droplet phase has been determined to create inhibitory properties. The dependencies of temperature decrease in a closed volume on extinguishing time have been found.