Short Communication

Abstract

The ignition and behavior of candle flames was observed photographically in free-fall (drop tower) tests under 19%-25% 02 concentrations in a nitrogen-diluted, I atm environment. A few tests were also conducted with helium dilution and with ignition in normal gravity. Compared to normal gravity. the microgravity flames were of lower power and greater sphericity. When a candle burning in normal gravity was released into microgravity, the flame shape changed immediately from the classical tear-drop to a sphere; the visible soot diminished throughout the test time. Tests with a longer duration of microgravity are being pursued in order to study extinction behavior, flame interactions, and burning rates.