The methane Raman spectrum up to 5500 cm-1. Application to the diagnostic of temperature in combustion media

The methane Raman spectrum from 1200 to 5500 cm(-1): A first step toward temperature diagnostic using methane as a probe molecule in combustion systems

International audience; We present a study of the spontaneous Raman spectra of (CH4)-C-12 from 1200 to 5500 cm(-1) at various temperatures. This study is of interest from a fundamental as well as from a practical point of view with regards to the temperature diagnostic in hydrocarbon combustion. The present investigation shows that the spontaneous (CH4)-C-12 Raman spectra are very sensitive to temperature and that the complexity of methane spectra is not an obstacle to use methane as a probe molecule in laser-diagnostic techniques. Our study consists in determining the polarisability parameters of methane (CH4)-C-12, unknown at the present time, from spontaneous Raman spectra recorded at pr…

CARS spectroscopy of CH4 for implication of temperature measurements in supercritical LOX/CH4 combustion

International audience; Experimental and theoretical investigations of coherent anti-Stokes Raman spectroscopy of CH4 have been carried out. Experimental spectra were measured in a heated high-pressure test cell and compared with numerical simulations. Good agreement was obtained for the temperature and the pressure dependence of CARS spectra in the ranges 300-1100 K and 0.1-5.0 MPa. The observed dependencies provide useful guidance for CARS thermometry, allowing quantitative measurements of temperature in high-pressure combustors. Application of multiplex CH4 CARS thermometry for single-shot measurements in a LOX/CH4 combustion at high pressure was demonstrated at supercritical conditions …

CARS methane spectra: Experiments and simulations for temperature diagnostic purposes

International audience; CARS laboratory experiments were done in the 2905-2925 cm(-1) range, in the vicinity of the v, band of the methane molecule, for pressures ranging from I to 50 bar, and temperatures up to 1100 K. These experiments were carried out in order to retrieve the pressure evolution of the CH4 spectrum, as well as to confirm its temperature dependance. After a brief recall on the theory used to compute pressure broadening coefficients and relaxation rates, we consider the v(3) and v(4) infrared bands of methane for benchmark calculations purposes. Next, we present recent experimental CARS spectra and calculated ones. Lastly, we discuss flame experiments as well as comparisons…