Research Of Correlation About Inert Gas Fire-Extinguishing Systems

Constructive fire safety is an eternal theme in human survival environment and fighting fire. Because the inert gas fire-extinguishing systems put out a fire without extinguishing agent, and all volatilization, and harmless of environment, it is called clean fire-extinguishing system . Widely used in place of electronic communication equipment, its protective objects gradually expand to several fields.In this paper, through using a kind of general software called computational fluid dynamics (CFD) and the numerical simulation method, the flow field of nozzle of inert gas fire-extinguishing systems was simulated and researched. A curve of P-Q of the nozzle was obtained by post-processing software. And it was concluded that the feasibility of the simulation by comparing with the obtained once before. Secondly, at the different pressure and different flow conditions, some change rules about velocity field and concentration field in the room in extinguishing system under control were drawn by changing the inlet pressure of the nozzle for setting and UDF programming. At last, a simplified gas fire-extinguishing system was designed. And through numerical simulation, flow parameters change in the process of inert gas spewing out the system were drawn and the pressure value of the orifice plate before was compared with the one calculated by using the formula in the norm.Through numerical simulation, some conclusions were drawn as follows. The larger the value of the inlet pressure is, the more fast the mass fraction of O2 in the room reduces, but indoor oxygen distribution is not uniform. Secondly, the larger the value of the inlet pressure is, the greater the speed of the jet gas is. When the value of an average of the inlet pressure is 3.5MPa, the speed from room bottom 1-m place is already higher than 30 meters per second. Thirdly, because of the pressure relief opening, the value distribution is not symmetrical in the cut-slide of Y=0, and the speed on the cut-slide along with the indoor vertical direction also is not the same. Fourthly, the pressure value of the orifice plate before is not precise by calculating the formula in code for design of gas fire extinguishing systems.