Abstract
The effects of a co-flow of oxygen-enriched air on the characteristics of a laminar jet diffusion flame of methane are experimentally investigated using a coaxial burner positioned vertically. The volume content of oxygen varies from 21% (air) to 30%. Flame structure is observed through the heights of flame lift-off and flame length based on initial rates of CH
4
, air, and oxygen percentages. Stability diagrams showing the states of the flame and transitions between these states are drawn. The reduction of the lift-off height observed during the addition of oxygen is explained by the increase of the laminar flame speed and heat release due to a higher flame temperature.