The candle flames in microgravity

The analysis of transient process of candle flame from normal gravity to mi-crogravity shows that the variation of the aerodynamic feature is much faster than that of transport feature. The candle flame temperature was measured by the use of an interferometer in microgravity. The results show that candle flame temperature in microgravity is indeed lower than that in normal gravity. The candle flame temperature in microgravity at 21%O₂ /79%N2 concentration is lower than the threshold temperature of soot formation of 1300K. That is the reason why the candle flame is dim blue at microgravity. However, if the ambient oxygen concentration is high enough, the candle flame temperature will be higher than the threshold temperature, so that soot will produce, and the color of candle flame will be bright yellow all the time even in microgravity.