Flame Flashback Investigations in Hydrogen-Enriched Low Swirl Flames using High-Speed Hydroxyl (OH) Planar Laser-Induced Fluorescence

Conference · Mon May 13 00:00:00 EDT 2024

OSTI ID:2349346

Parajuli, Pradeep ^[1]; Strakey, Peter ^[2]

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1. NETL Site Support Contractor, National Energy Technology Laboratory
2. NETL

This study reports flashback mechanism observed in hydrogen-enriched flames stabilized in a low swirl burner (LSB) at atmospheric pressure and temperature conditions. The fundamentals of hydrogen-rich stable flames and spatiotemporal investigation of flashback phenomena were observed experimentally using a high-repetition-rate nanosecond (ns)-duration hydroxyl radical planar laser-induced fluorescence (OH-PLIF) diagnostic. Testing was conducted in an optically accessible pre-mixing section of LSB with inlet pre-mixing velocities from 5 to 10 m/s for methane and hydrogen (50 – 90% by mole) blends. Swirlers with two different turning angles, 26 and 33 degrees and three different perforated plate hole diameters, 1.08, 1.12 and 1.16 mm with measured swirl numbers varying from 0.43 to 0.49 were used. The flashback propensity showed dependence on the proximity of the lifted flame to the burner exit which was dependent on pre-mixer velocity, hydrogen content and equivalence ratio (ER). High-speed OH-PLIF images revealed lifted flames were first observed at low ER condition which is changed to M-shaped flame attached to burner rim with the increase in ER. Then, further increase in ER triggers flame flashback into the nozzle. Flashback occurred when burning occurs in the outer shear layer and the leading flame brush ingresses into the nozzle.

• Research Organization: National Energy Technology Laboratory (NETL), Pittsburgh, PA, Morgantown, WV, and Albany, OR (United States)
• Sponsoring Organization: FE - USDOE Office of Fossil Energy and Carbon Management (FECM)
• OSTI ID: 2349346
• Country of Publication: United States
• Language: English