Mechanisms of Flame Stabilization and Blowout in a Reacting Turbulent Hydrogen Jet in Cross-Flow

Journal Article · Wed Aug 01 04:00:00 EDT 2012 · Combustion and Flame

DOI:https://doi.org/10.1016/j.combustflame.2012.01.012· OSTI ID:1047942

Kolla, H; Grout, R W; Gruber, A; Chen, J H

The mechanisms contributing to flame stabilization and blowout in a nitrogen-diluted hydrogen transverse jet in a turbulent boundary layer cross-flow (JICF) are investigated using three-dimensional direct numerical simulation (DNS) with detailed chemistry. Non-reacting JICF DNS were performed to understand the relative magnitude and physical location of low velocity regions on the leeward side of the fuel jet where a flame can potentially anchor. As the injection angle is reduced from 90{sup o} to 70{sup o}, the low velocity region was found to diminish significantly, both in terms of physical extent and magnitude, and hence, its ability to provide favorable conditions for flame anchoring and stabilization are greatly reduced. In the reacting JICF DNS a stable flame is observed for 90{sup o} injection angle and, on average, the flame root is in the vicinity of low velocity magnitude and stoichiometric mixture. When the injection angle is smoothly transitioned to 75{sup o} a transient flame blowout is observed. Ensemble averaged quantities on the flame base reveal two phases of the blowout characterized by a kinematic imbalance between flame propagation speed and flow normal velocity. In the first phase dominant flow structures repeatedly draw the flame base closer to the jet centerline resulting in richer-than-stoichiometric mixtures and high velocity magnitudes. In the second phase, in spite of low velocity magnitudes and a return to stoichiometry, due to jet bending and flame alignment normal to the cross-flow, the flow velocity normal to the flame base increases dramatically perpetuating the blowout.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); National Renewable Energy Laboratory (NREL), Golden, CO.
• Sponsoring Organization: USDOE Office of Science, Basic Energy Sciences; USDOE Office of Energy Efficiency and Renewable Energy
• DOE Contract Number: AC36-08GO28308
• OSTI ID: 1047942
• Journal Information: Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 8 Vol. 159; ISSN CBFMAO; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ALIGNMENT
BENDING
BLOWOUTS
BOUNDARY LAYERS
CHEMISTRY
COMBUSTION
Computational Sciences
FASTENING
FLAME PROPAGATION
FLAMES
HYDROGEN
MIXTURES
SIMULATION
STABILIZATION
STOICHIOMETRY
TRANSIENTS
VELOCITY