Influence of Hydrogen Addition on Flow Structure in Confined Swirling Methane Flame

• Published in: Journal of propulsion and power 2005-01, Vol.21 (1), p.16-24
• Main Authors: Wicksall, Donald M, Agrawal, Ajay K, Schefer, Robert W, Keller, Jay O
• Format: Article
• Language: English
• Subjects: Swirling
• ISSN: 0748-4658; 1533-3876
• DOI: 10.2514/1.4235

The flowfield of a lean premixed swirl-stabilized burner simulating typical features of land-based gas-turbine combustors was investigated using particle-image velocimetry. Fuel and air were premixed upstream and burned at atmospheric pressure in a quartz-tube combustor operated at a theoretical swirl number of 1.5. Instantaneous-velocity-field measurements were obtained for a nonreacting flow, a methane flame, and a hydrogen-enriched methane flame. Flow measurements were used to obtain two-dimensional vorticity and normal-strain, turbulentkinetic-energy, and kinetic-energy-dissipation-rate fields. Results show that the average- and instantaneous-velocity fields were affected by the addition of hydrogen to methane. The instantaneous-velocity fields showed smaller eddies that were not present in the time-averaged fields. Higher values of turbulent kinetic energy were observed in the jet region of the methane flame, suggesting the unsteady nature of combustion. The instantaneous vorticity and normal strain were four to seven times higher than the averaged values, indicating the importance of smaller vortical structures to local flame-extinction phenomena.