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ABSTRACT
The focus of this research was the design, fabrication, and testing of an experimental non-premixed flame burner to determine the effect of gaseous flow parameters and flow geometry on the stability of methane/oxygen combustion. The non-premixed burner consisted of a horizontally mounted, rectangular combustion chamber with a single coaxial injector, capable of introducing reactants at a specified impingement angle of 30° at the exit plane. Gaseous oxygen was the primary flow and gaseous methane was the secondary flow. The non-premixed burner was equipped with optical windows on both sides of the chamber parallel to the axis of the flame, which allowed for clear viewing of the product flame. Ignition of the reactants was achieved by a retractable spark plug. Stability maps of the resultant diffusion flame were created for three different injection flow areas based upon reactant equivalence ratio and primary reactant Reynolds numbers. The results showed that decreasing the primary flow area resulted in a more stable flame condition over a broader range of Reynolds numbers (laminar flow to over 40000) and equivalence ratios (fuel-lean 0.27 to fuel-rich 4.94). Increasing Reynolds number also resulted in a transition from a stable, anchored flame to a detached, unstable flame.
Nomenclature
| CRES | = | Corrosion resistant stainless-steel |
| D | = | Diameter of flow, mm |
| GCH4 | = | Gaseous methane |
| GH2 | = | Gaseous hydrogen |
| GN2 | = | Gaseous nitrogen |
| GO2 | = | Gaseous oxygen |
| L | = | Length, mm |
| (O/F) | = | Oxidizer-to-fuel ratio |
| P | = | Pressure, kPa |
| Pox | = | partial oxidation |
| Re | = | Reynolds number |
| V | = | Velocity, m/s |
| XSTO | = | Non-dimensional average flame standoff distance |
| Greek Symbols | = | |
| Φ | = | Equivalence ratio |
| Subscripts | = | |
| Annular | = | Annular region of coaxial injector |
| CH4 | = | Methane |
| D | = | Diameter |
| H | = | Hydraulic |
| Mass | = | Mass |
| Mole | = | Mole |
| Mom | = | Momentum |
| O2 | = | Oxygen |
| SD | = | Standoff distance |
Acknowledgments
The authors wish to thank the Penn State Altoona Research and Sponsored Programs office and Mr. Corey Griffin for sponsoring this internal research grant. Thanks to Mr. Morgan Litzinger, Mr. Lucas Nunamaker, and Mr. Jordan Crist for design, fabrication, and initial checkout testing of the experimental diffusion burner chamber. Special thanks to Mr. Tom Hatch for machining of the spark plug igniter pneumatic cylinder mounting bracket, Mr. Dillon Over for assistance with upstream flow manifold assembly, Mr. Joshua Hollingshead for assembly work, machining, test assistance, and welding of the experimental cart, and Mr. Sydney Damgaard for assistance in video cinematography data review.