Influence of Microwave on Methane-Air Laminar Flames

The influence of microwave on methane-air premixed and diffusion flames was investigated in this work. The burned-gas temperature, brightness and electron temperature were measured for a flame situated in a cavity resonator excited in the TE011 microwave (2.45 GHz) resonant mode. The burned-gas temperature was measured with a radiation thermometer by observing the radiation from the end of the optical fiber inserted into the flame. The change of brightness was obtained with a photomultiplier tube. The electron temperature was estimated by the equivalent resistance method with double-floating electrostatic probes. While the burned-gas temperature increases by a few degrees, the electron temperature increases substantially with an increase of the microwave power introduced to the cavity. The brightness of the diffusion flame which is ascribed to the radiation of carbon particles, increases with an increase of microwave power.