Strain rate and flame maximum temperature histories of evolving jet diffusion flame were experimentally investigated.
The diameter and the tip penetration distance of fuel primary vortex were measured from the visualization with shadow system and a high speed camera. And, through a similarity between a stagnant point diffusion flame(Tsuji burner) and an evolving jet diffusion flame, histories of strain rate for evolving process were examined. It is shown that a flame does not respond to changing flow field simultaneously.
Temperature measurement was performed with a fine wire thermocouple. Because a thermocouple contacts a flame sheet in an instant, a compensation using time constant was needed to gian flame maximum temperature. The time constant changes in velocity and thermal field. Generally, methods of estimating time constant are used to measure fluctuating temperature with mean but evolving jet diffusion flame is not so, in other words it does not have a mean temperature. Therefore a time constant was experimentally estimated in a instant velocity and a flame maximum temperature by new idea. And the time constant was applied to evolving jet diffusion flame. It is shown that the flame maximum temperature is related to a strain rate and as a strain rate increases, a flame maximum temperature decreases.
