Abstract
Aim: The problem of fire safety of areas protected by fixed gaseous extinguishing system is discussed. Increasing the accuracy and reliability of the modeling of gas extinguishing process can be achieved by using methods of computational fluid dynamics CFD using ANSYS FLUENT software. The aim of the study was to develop a numerical CFD model of extinguishing gas flow of the protected space and to examine the extinguishing effectiveness of particular type of norm gases and newly proposed extinguishing gas mixtures with a density similar to the density of air, which significantly limited the phenomenon of outflow of gas from the room and allowed to get longer retention times.
Project and methods: The paper proposes a numerical model of extinguishing gas flow through the room which was developed using ANSYS Fluent program, the description of experimental researches carried out in real scale and analytical calculations based on the norm model of gas flow through the room carried out to validate the created CFD model. Examples of practical use of CFD model for simulation, results of which can provide information to support the design of fixed gaseous extinguishing systems were presented.
Results: On the basis of a comparative analysis of the collected simulation results model Standard k-ε was indicated as a model that provides the greatest convergence of test results in real scale. Retention times obtained by the computer simulation were closer to real scale results than the retention times obtained on the basis of calculation using the norm wide interface model.
Conclusions: The use of CFD modeling allows to review the mechanism of gas flow through the room with greater accuracy than previously used models. This allows for optimal selection of the type and amount of extinguishing gas due to the retention time. Selection of extinguishing gas with the mixture density similar to air density, makes it possible to obtain a retention time exceeding the retention time of the gases specified in the applicable standards. The use of CFD modeling allows to conduct research using virtual space, eliminating the danger related to measurement process posing a threat to humans and reduce financial costs associated with the discharge of extinguishing gas.
Keywords: fixed gaseous extinguishing system, inert gases, clean extinguishing agents, retention time, model of gas flow through the room, computational fluid dynamics CFD
Type of article: short scientific report