Burning Velocity Measurements and Simulations for Understanding the Performance of Fire Suppressants in Aircraft - Letter Report Prepared for Meggitt
Gregory T. Linteris, John L. Pagliaro
As described by Reinhardt and co-workers , overpressure in the FAA Aerosol Can Test (FAA-ACT) has been observed for the halon replacements HFC-125, Novec 1230, and 2-BTP when added at sub-inerting concentrations. Work by Linteris and co-workers [2-5] has used experimental measurements of the flammability limits, explosion pressure and burning velocity, together with equilibrium, stirred-reactor, and premixed flame speed simulations to interpret the overpressure. Additional investigations were performed to validate the kinetic mechanisms and understand the chemical reaction pathways for the pure agents in air [6-11]. The goal of the present work is to predict the overpressure behavior of two proprietary blends (each a 50 % mass fraction of CO2 with either Novec (C6F12O, Novec 1230) or 2-BTP (C3H2F3Br, 2-Bromo-3,3,3-trifluoropropene), hereafter referred to as Blend A or Bland B, respectively) using the techniques and understanding developed in the previous work. To this end, experimental measurements of the flammability limits, explosion pressure, and premixed flame speed have been made, under conditions believed to provide the most insight into the blends behavior in the FAA-ACT. Following the approaches developed in prior work, equilibrium, stirred reactor, and premixed flame speed simulations have also been performed to interpret and predict the behavior of the agents in the FAA-ACT. Reviews of the concepts and experimental approaches are given as necessary so that the results provided can be comprehensively interpreted.