Flow and release characteristics of a potential Halon substituent CF3I influenced by filling density and pressure

Halon fire-extinguishant has been banned by the Montreal Protocol due to the ozone-depleting effect, and CF3I is proposed as a promising alternative to Halon on aircraft cargo compartments. The filling density and filling pressure of CF3I in the fire-extinguishing vessel are critical for the design of onboard fire-extinguishing system. Therefore, this paper combines experimental test and quantitative computational fluid dynamics numerical simulation to explore flow and release characteristics for CF3I under five sets of filling densities and five sets of filling pressures. The increase in filling density and the decrease in filling pressure are unveiled to promote the evaporation of CF3I. In addition, a release parameter of R is herein proposed to quantitatively assess the release efficiency of CF3I under varying conditions, and the recommended ranges of filling density (514–1028 kg/m3) and filling pressure (2.5–3.5 MPa) are accordingly proposed for CF3I. As revealed by the monitored phase transition mass transfer rate, Halon 1301 can be evaporated at the pipeline inlet from the beginning of the agent discharging process, while CF3I only evaporates when approaching the nozzle at the later stage of the agent release process.