Combustion promotion and extinction of premixed counterflow methane/air flames by C₆F₁₂O fire suppressant

Abstract

Along with the phase-out of CF3Br (Halon 1301), several agents have been proposed as halon replacements for use in suppressing fires in aircraft cargo bays. However, these potential drop-in replacements were found to have a promotion effect on the explosion of an aerosol can, which tested by the US Federal Aviation Administration. Motivated by this problem, we measured the laminar burning velocity of premixed methane/air flames with added one of these agents, C6F12O (Novec 1230), in the counterflow configuration, for fuel/air equivalence ratios of 0.63, 0.68, 0.74, and 0.82. C6F12O was added at levels up to 3.5% by volume fraction to each mixture. Numerical simulations were performed using the detailed kinetic mechanism. The predicted results were in good agreement with the experimental measurements. The burning velocity for the very lean flames ( Φ = 0.63) was increased with C6F12O added at low concentrations due to the additional heat release from C6F12O reaction, whereas for higher equivalence ratios ( Φ = 0.68–0.82), it always decreased with all added agent concentrations. The extinction stretch rates have also been measured using the counterflow technique to gain further insight into the promotion/inhibition behavior of C6F12O in ultra-lean ( Φ < 0.63) flames. The results showed that C6F12O has larger promotion effect for the ultra-lean conditions. Sensitivity analyses showed that lean flames are more sensitive to the fluorinated reactions compared to the rich. In addition, direct images of hydrocarbon flame inhibition by fluorinated ketone were provided for the first time to help interpret the experiments.

The Efficiency of Dodecafluoro-2-Methylpentan-3-One on Suppressing the Lithium Ion Battery Fire

“…10 presents the reaction pathways of C6F-Ketone decomposition. When the activity of free radicals generated by the decomposition extinguishing agent is sprayed to the protection zone, flame or fire extinguishing agent contact hot surfaces, the radical chain reaction seize combustion generated active substances, destruction combustion process chain transfer, and ultimately achieve the purpose of extinguishing the ways a chemical fire, cooled, diluted or cut off the air and other physical effect is minimal [29].…”

“…8 The experimental set up of Case 4 (a) 859 s after oven heated the battery, the dropped electrolyte was ignited (b) 2 s after ignition, both cathode and anode caught on fire (c) The agent was applied at 3 s after ignition (d) The fire was under control, 24 s after ignition the fire was put outFig. 9The LTO battery fire extinguishing process using C6F-ketone in Case Reaction pathways of C6F-Ketone decomposition[29].…”

Compatibility between C6F12O–N2 Gas Mixture and Metal Used in Medium-Voltage Switchgears

“…Chemical formula C Currently, C 6 F 12 O is only used as a fire-extinguishing agent and covering gas for magnesium treatment as well as two-phase immersion cooling systems, which is safe to use and relatively low in cost [26]. Furthermore, research on C 6 F 12 O as a gas-insulating medium has just started [27][28][29][30]. However, due to its high boiling point, C 6 F 12 O cannot be used as an insulating medium alone; that is, it must be mixed with a buffer gas, such as N 2 or CO 2 .…”

Combustion Inhibition of Aluminum–Methane–Air Flames by Fine NaCl Particles

“…After a group of test runs, the volumetric flow rate of the carrier gas was fixed at 5.5 standard liters per minute (SLPM, at 0 °C and 1 atm). During the experiments, the burner assembly and pipelines were heated using a of the burner implemented several technical solutions considered previously in the building of nozzle burners [26,27]. In particular, it used a profiled converging nozzle to reduce the boundary layer thickness and to yield a top-hat (plug-flow) velocity profile at the exit plane.…”