МЕХАНИЗМ ГЕНЕРАЦИИ САМОВСПЕНИВАЮЩЕЙСЯ ГАЗОАЭРОЗОЛЕНАПОЛНЕННОЙ ПЕНЫ
Authors: Д.В. Федоткин 
Published: December 2024

В статье представлены теоретические основы применения конденсационного метода получения дисперсных систем для получения самовспенивающейся газоаэрозоленаполненной пены. Показано, что использование твердотопливных генераторов давления является наиболее перспективным для реализации конденсационного метода получения пены в целях пожаротушения. Приведены результаты оценочных расчетов для получения самовспенивающейся газоаэрозоленаполненной пены с учетом растворимости газов, образующихся при сгорании твердотопливных генераторов давления. Для различных диаметров трубопроводов приведены оценки максимальных расчетных значений расхода при подаче самовспенивающейся газоаэрозоленаполненной пены в зависимости от давления в установке. Представлены основные этапы реализации технологии получения самовспенивающейся газоаэрозоленаполненной пены.

The application of the classical (dispersion) method of air-mechanical foam production with the use of foam generators does not allow to effectively extinguish fires in tank farms. The application of the condensation method of foaming is promising due to changes in the parameters of the physical state of the system, in particular, pressure increase and decrease. This method of almost instantaneous foaming, we can apply the term “self-expanding”, serves as a vivid illustration of the well-known Henry’s law. The processes of gas extraction from water (desorption) and dissolution of gases in water (absorption) obey the general laws of mass transfer in the liquid-gas system and proceed until equilibrium is reached, depending on temperature, pressure and concentrations in both phases. It is this method that is used in the elaborated technology for obtaining self-expanding gas-aerosol-filled foam. To create pressure in a container with a foaming agent solution, solid fuel pressure generators are used, which are aerosol-forming gas-generating compositions similar to those used in aerosol fire extinguishing. A solid fuel pressure generator, depending on the properties of the aerosol-forming gas-generating composition, releases a wide range and amount of gases during combustion: nitrogen, carbon dioxide, carbon monoxide, water vapor and micron-sized potassium compounds (carbonate, potassium bicarbonate, etc.). The main criteria are the maximum gas release during combustion, as well as a significant percentage of the formation of extinguishing gases (nitrogen, carbon dioxide, etc.) from the total gas release during combustion. A calculated estimate was carried out to obtain a self-expanding gas-aerosol-filled foam in a 7 m3 container with a foam tank used to separate storage of water and  concentrate of foaming agent, taking into account the solubility of nitrogen and carbon dioxide. Taking into account the results of earlier studies, there have been calculated peak flow rates of self-expanding gas-aerosol-filled foam when using pipelines with diameters of 219 and 159 mm. Practical realization of such flow rates when extinguishing fires in tanks is one of the key points allowing to cover the whole area of the burning tank with foam in seconds. The main stages of the implementation of the technology for obtaining self-expanding gas-aerosol-filled foam are formulated.