Blowoff and emission of rich-lean Co-axial burner

摘要

Blowoff and emission of methane-air rich-lean co-axial burner was tested at pressure of 0.1 MPa, temperature ranged from room temperature to 673 K, and equivalence ratio of outer gas and inner gas kept smaller than 1. Concept of rich-lean co-axial burner is that the lower-NOx inner-flame dilutes and freezes the higher-NOx outer-flame while the lower-velocity outer-flame prevents the faster-velocity inner-flame from blowoff. It has a continuous flame surface from outer to inner, and an extinction zone between flame lip and outer rim. Results show that NO{sub}x emission measured ranged about 2 ppm, depends on Φ{sub}(avg). Ratio of critical blowoff velocity, U{sub}(in)/U{sub}(out) becomes constant if gas composition is fixed. It suggests that low NO{sub}x and stable flame region spread over wide range when Φ{sub}(avg) is kept at low value.