A three-dimensional positioning, fast insertion thermocouple was used to measure the gas temperature in ethylene/air inverse diffusion flame at different measuring points, and based on the theory of thermocouple particle densitometry, the soot fraction volume in the flame at different points were calculated, with the aim to study the distribution characteristics of gas temperature and soot fraction volume in the inverse diffusion flame. The results have been shown that the gas temperature decreased in the axis direction, and so in the radius direction, and the gas temperature at the burner exit was low due to the exit effect. Soot fraction volume presented inverse correlation with gas temperature, it increased in the axis direction and got the maximum value at the flame tip, the values at flame front were higher than that of in the center, which showed low temperature promoted soot formation, soot incepted, grew and oxidized along with the flame propagated.

Key words: inverse diffusion flame, soot, fraction volume, thermocouple particle densitometry