(148f) Measurement of Temperature Distribution Over 2000°C in Premixed Flame by Using Laser Speckle Method

Temperature distribution of premixed flame over 2000°C between methane gas and air has been developed using laser speckle method. The inner diameter of the pipe exit was 13mm. The gas flow rate of methane changed from 0.7 L/min to 2L/min. The flow rate of air was ten times of the methane flow rate. The premixed flame consists of two different kinds of flames. One is the internal flame which the maximum temperature is greater than 2000°C. The other is the diffusion flame around the internal flame. From the movie of the speckle patterns, it was found that the motion of the premixed flame was unsteady and oscillatory. The more methane flow rate made not only the longer the period of the oscillation but also the more the unsteady domain of the diffusion flame. Furthermore, from Fermat's principle and Gradstone-Dale's equation, the temperature distribution of the unsteady and oscillatory premixed flame was predicted.