Extinguishment of Cup-Burner Flames in Low Gravity
F Takahashi, Gregory T. Linteris, V Katta
The effects of oxidizer stream velocity and oxygen concentration, as well as gravity and pressure, on the extinguishment limits of laminar co-flow diffusion flames of methane, formed in a cup-burner apparatus, have been studied experimentally and computationally. A first attempt was made to measure the cup-burner minimum extinguishing concentration (MEC) of CO2 in microgravity ( g) aboard the NASA Reduced Gravity Aircraft (KC-135). Numerical simulations with detailed chemistry and radiative heat-loss models were performed to reveal the flame structure during the unsteady blowoff-type extinguishing processes and to predict the extinguishment limits. The MEC values determined for various oxidizing environments were:Experiment Computation Air/1g/1 atm (15.7 0.6) % 14.5 % (16.1 %) Air/1g/0.7 atm (15.4 0.5) % 13.5 % 30 % O2/1g/1 atm (34.0 1.2) % 31.0 % 30 % O2/1g/0.7 atm (32.4 1.1) % 29.9 % 21 % O2/ g/1 atm (21.4 0.7) % 19.1 % Considering the complex chemistry and flow-field interactions in the blowoff extinguishment processes, the predicted MEC values were consistently in good agreements (8 % less on average) with the measurements. The relatively high MECs of CO2 in oxygen-enriched environments point to a need for further trade-off studies of fire-extinguishing agents suitable for spacecraft and surface habitats in space exploration.
, Linteris, G.
and Katta, V.
Extinguishment of Cup-Burner Flames in Low Gravity, 43rd, Undefined, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=861350
(Accessed December 10, 2023)