Experiment on microscale flames stabilized on surface of annular porous media

The characteristics of the surface-stabilized flame on a porous medium in an annular microscale channel were studied experimentally with methane/air mixture. In the pressure drop characteristic study, three porous media with the same pore diameter and different porosities were used and compared. The substitution of the air for the mixture was verified accurately at first. Then the relationship expression of the air pressure drop characteristic was acquired for each porous medium according to the Forcheimer correlation. The third porous medium was selected for the following research, as it had the expression closer to the Darcy's law. As for the ignition characteristic study of the surface-stabilized flame, a reasonable criterion was established for the flammability limit determination. Based on the criterion, the result showed that the limit reached the minimum value when the mixture equivalence ratio was 0.9. During the extinction characteristic study, through the well-designed operating procedure, the experiment was conducted to obtain the strict extinction limit of the surface-stabilized flame. It was indicated that the extinction limit at mixture equivalence ratio of 0.8 was the least.