Effect of reactant preheating on the stability of non-premixed methane/air flames

Sylvain Lamige (1) , Cédric Galizzi (1) , Jiesheng Min (2) , J. Perles (1) , Frédéric André (1) , Françoise Baillot (2) , Dany Escudié (1)

1 CETHIL - Centre de Thermique de Lyon
2 CORIA - Complexe de recherche interprofessionnel en aérothermochimie

This study details the influence of reactant temperature on the stability of non-premixed CH4 /air co-flow jet flames. Flame characteristics have been studied for five temperature levels (from 295 K to 600 K). The hysteresis zone formed by the limits between attached and lifted flame translates towards higher methane jet velocities with an increase of initial temperature, independently of the air velocity range. Moreover, critical velocities vary linearly with initial temperature. In addition, attachment and lift-off heights have been obtained from CH* chemiluminescence visualization. Results point out that the attachment height decreases significantly with temperature. Observations also indicate that the intrinsic process of lifting is modified. Pre-lifting anchored flame local extinctions, not observed at room-temperature, appear at higher initial temperatures; their occurrence increases with temperature. The lift-off height of turbulent lifted flames is also reduced with temperature. Overall, results show that increasing local temperature in the stabilization zone enhances flame stability.

Domaines: Thermique [physics.class-ph]; Thermique [physics.class-ph]

Sylvain Lamige, Cédric Galizzi, Jiesheng Min, J. Perles, Frédéric André, et al.. Effect of reactant preheating on the stability of non-premixed methane/air flames. International Heat Transfer Conference, IHTC-14, Aug 2010, WASHINGTON, United States. pp.205-210, ⟨10.1115/IHTC14-22938⟩. ⟨hal-00541321⟩