Abstract: In order to study the fire extinguishing efficiency of mixed gas-liquid flow of C6F12O/N2, developed a fire extinguishing concentration test device of mixed gas and a two-phase flow fire extinguishing concentration test device based on a scaled fire extinguishing model. Then measured the fire extinguishing concentration of C6F12O/N2 and the two-phase flow fire extinguishing concentration of C6F12O after nitrogen atomization，and verified by full-scale fire extinguishing experiment. The results show that the fire extinguishing concentration of C6F12O gas and liquid after atomization is linearly positively correlated with the oxygen concentration. The scale fire extinguishing model can accurately measure the extinguishing concentration of liquid fire extinguishing agent after atomization, and the deviation is less than 1.36%. Based on the two-phase flow spray scheme mixed with C6F12O/N2, the fire extinguishing concentration of C6F12O was reduced by reducing the oxygen concentration in the protective space during the fire extinguishing process. At the same time, under the large?aperture nozzle, realized the low pressure, large flow atomization and rapid spray of C6F12O. Finally, through the physical fire experiment, the concentration and amount of C6F12O can be reduced by 27% under the fire extinguishing condition of 100 m3 total flooding.

Key words: perfluorohexane, nitrogen, synergistic fire extinguishing, fire extinguishing concentration, total flooding test