Candle flame temperature measurement in microgravity by differential interferometry

The differential interferometer developed for the candle flame temperature measurement in microgravity was introduced in principle. A calculation procedure for the interpretation of the differential interferogram into temperature distribution was presented. The results show that the candle flame temperature is below the soot formation threshold temperature in quiescent microgravity environment. Due to the absence of gravity-induced gas flow, the chemical reaction rate is controlled by the diffusion rate of various species. The importance of radiative heat loss of the candle flame is enhanced, which results in the low candle flame temperature in quiescent microgravity. It partially justifies the argument that the dim blue phenomenon of candle flame in microgravity results from the low candle flame temperature.