Study on Dispersion Characteristics of FK5112 Mixed with Inert Gas

Abstract

New clean agent fire suppressant, Perfluoro-2-methyl-3-pentanone, also known as FK5112 or Novec 1230 has excellent environmental behavior and high efficiency, and has been considered as one of the most promising halon replacement extinguishing agents. However, its high boiling point and poor dispersibility has largely restricted further application. To address the issue, our present work proposes the novel method by introducing inert gas mixed with FK5112 to improve the agent dispersibility. The evaporation mechanism of FK5112 during the mixing has been demonstrated in detail, and the droplets evaporation time of FK5112 affected by the diameter, the partial pressure of vapor, and the diffusion coefficient of different inert gas is estimated. Our results show that the droplets size of FK5112 have significant effect on evaporation, as it takes only 0.076s for a 5µm droplet to completely evaporate in N2 even if the partial pressure is high(a=80%). After FK5112 has evaporated in the inert gas, dispersion properties of the binary agent have been calculated and discussed thoroughly. The precise equation to estimate the vapor pressure of FK5112 is selected and the relation with the boiling point, mixing ratio, and pressure of the binary agent is revealed. For the 20% mixing ratio of FK5112, the boiling point of the mixture can reach 8.49°C and for the 10% mixing ratio, the boiling temperature is -5.85°C, which shows mixing with inert gas could notably improve its dispersibility. Additionally, mixing ratio and droplets size of FK5112 have shown a great impact.