Reduction of radiant heat flux by “SOGDA” fire barrier

Abstract

Introduction. The innovative technology of heat flux reduction implemented using the heat-shielding water-film barrier “SOGDA” (model 1), according to the results of previous experimental studies, allows to reduce the radiant heat flux by more than 50 times. However, the thermal and physical mechanisms of this process are not sufficiently studied, which does not allow to justify the technical characteristics of heat shields under given conditions for their operation. Purposes and objectives. The purpose of the article is to evaluate experimentally and theoretically the coefficient of the reduction of radiant heat flux by a heat-shielded water-film fire barrier under the “standard” fire mode. To achieve this, a mathematical model was developed for calculating the coefficient of reduction of radiant heat flux by the fire barrier, an assessment was made of the physical mechanisms of the reduction of radiant heat flux by a fire barrier, and an experimental time dependence of the density of radiant heat flux passing from a small oven through the barrier installed in one of its walls to the outside was obtained. Methods. There are used a theoretical method for calculating radiant heat transfer based on the Stefan-Boltzmann equation and an experimental method for studying the reduction of radiant heat transfer in a small-sized furnace for testing building structures for fire resistance in the “standard” fire mode. Results. The physical mechanisms of the reduction of radiant heat flux by the fire barrier are substantiated. It is shown that the fire barrier with a size of 1.5´1.5 m at a temperature inside the furnace 1030 °C absorbs, reflects and disperses 99 % of the radiant heat flux incident on it. Experimental time dependence of the density of the radiant heat flux at a distance of 0.5 m from the geometric center of the unheated surface of the barrier is obtained. It is found that in the case of the “standard” fire, the coefficient of reduction of radiant heat flux by the fire barrier “SOGDA” (model 1) varies depending on the time from the onset of natural gas combustion in the range from 380 to 80. The conclusion. Further experimental studies will be aimed at a more detailed study of the thermal and physical mechanisms for the reduction of a radiant heat flux through the barrier, which will allow us to justify the technical characteristics of heat shields under given conditions for their operation without additional experimental studies.