抄録
The effect of ambient balance gas on the flame-spread rate over a PMMA sheet was investigated experimentally under microgravity and normal-gravity conditions. N2, CO2, He and Ar were used as the balance gas in order to change the gas properties such as heat conductivity, heat capacity and absorption coefficient. The result shows that the impact of the difference of the ambient gas on the spread rate is different between normal gravity and microgravity conditions. In normal gravity, thermal conductivity and the heat capacity are the dominant factors, and the spread rates are He>N2=Ar>CO2 with high O2 level. On the other hand, in microgravity, the absorption coefficient and thermal diffusivity play great roles, and the spread rates with CO2 balance are much enhanced in a quiescent condition whereas that with He balance is suppressed.
