Multiscalar Analyses of High-Pressure Swirl-Stabilized Combustion via Single-Shot Dual-SBG Raman Spectroscopy

Abstract

We report an experimental study and thermochemical analysis of high-pressure swirl-stabilized combustion utilizing subframe burst gating (SBG) Raman spectroscopy. SBG Raman spectroscopy is a novel diagnostic technique that provides increased accuracy of quantitative scalar measurements in a single-shot pointwise manner. A recent modification of our original system allows parallel detection of both Stokes and anti-Stokes spectral components (hence the term dual SBG). We begin by briefly describing the experimental construction of a Raman calibration matrix, which allows us to reduce spectral cross-talk in the measurements. Next we describe the application of dual-SBG Raman spectroscopy to simultaneous single-shot measurement of temperature and species mass fractions in a turbulent flame stabilized over a lean-direct-injection (LDI) burner using gaseous methane fuel at elevated pressure of 17 atm. Our discussion includes the practical challenges of Raman spectroscopy in a pressurized combustion rig. Statistical analyses of the single-shot thermochemical data provide insights into the nature of the partial-premixing process and its impact on the subsequent combustion process.

Keywords:

• Combustion diagnostics
• High-pressure combustion
• Raman spectroscopy
• Scalar analysis
• Turbulent flow

ACKNOWLEDGMENTS

This work was supported principally by the Fundamental Aeronautics Program's Supersonics Project at NASA John H. Glenn Research Center. The authors acknowledge Quang-Viet Nguyen for his long advisory support on the project and the manuscript of this paper; and Greg Calhoun, Derek Podboy, and Kurt Rusmisel for their assistance in the construction and operation of the facilities. The authors are very thankful to J.-Y. Chen for his laminar flame calculations.

Notes

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