AbstractsEngineering

Microgravity droplet combustion experiments were performed in atmospheres with elevatedconcentrations of CO2 at pressures of 1.0 atm, 3.0 atm, and 5.0 atm to examine theeffects of a radiatively participating gas commonly used as a fire suppressant in space applications.Results were obtained from two unique experimental platforms, NASA GlennResearch Center’s 5.2 second drop tower (i.e., the Zero Gravity Facility “ZGF”) and theInternational Space Station (ISS). Tests performed in the ZGF deployed methanol andn-heptane droplets, with initial diameters ranging from 1.25 mm to 2.0 mm, onto a 120micron quartz fiber. Tests performed on the ISS deployed n-heptane droplets with initialdiameters ranging from 2.0 mm to 4.0 mm and were were either freely deployed or tetheredwith an 80 micron SiC fiber. Ambient atmospheres comprised 21% O2 with variousconcentrations of CO2 ranging from 0% to a maximum of 70% by volume with a balanceof N2 . Results are reported showing the effects of a thermally participating gas atatmospheric and elevated pressures on the fuel droplet’s average burning rates, sootingpropensity and, in the case of methanol at 1 atm, on its unique extinction mechanism. Advisors/Committee Members: Tien, James (Advisor).