抄録
Temperature distribution of premixed flame between methane gas and air has been measured using laser speckle method. The gas flow rate of methane changes from 0.9 l/min to 1.2 l/min. The flow rate of air is ten times of methane gas flow rate. The flame is almost steady state due to the visualization. On the other hand, from the movie of speckle patterns, the motion of the premixed flame is unsteady and oscillatory. The more methane flow rate makes the more the unsteady domain of diffusion flame. Furthermore, from Fermat's principle and Gladstone-Dale's equation, the temperature distribution of the unsteady and oscillatory premixed flame has been predicted.
