CARS investigation of hydrogen Q‐branch linewidths at high temperatures in a high‐pressure H₂–O₂ pulsed burner

Abstract

Hydrogen Q-branch rotational component line-broadening coefficients for hydrogen-water collisions were determined at 2700 K. For linewidth measurements CARS spectroscopy with a Fabry-Perot interferometer and a multichannel detector was applied. In order to perform these experiments, a high-pressure pulsed hydrogen-oxygen burner with variable and controlled pressure was designed. Temperature measurements inside the burner were performed simultaneously with the help of broadband CARS spectroscopy.

Coherent anti‐stokes Raman spectroscopy investigation of collisional broadening of the hydrogen Q‐branch transitions by water at high temperatures

“…The results of the measurements of the Q 1 , Q 3 , Q 5 , and Q 7 line-broadening coefficients at T ³ 2700 K, fulfilled in a hydrogen-oxygen combustion chamber, 6 were in good agreement with this extrapolation.…”

“…The three-channel measurement setup and the pulsed chamber have been described elsewhere. 6,7 The combustion process was repetitive with a rate of 1 Hz. After the H 2 -O 2 mixture burned out, the outflow of the gas from the combustion chamber led to a drop in the pressure and temperature.…”

Single‐shot high‐resolution dual‐broadband CARS interferometric lineshape spectroscopy

“…In our previous experiments, 4 we developed a highresolution spectroscopic technique that allows single-shot CARS spectra of hydrogen Q-branch molecular transitions to be obtained in non-stationary media with a resolution of ¾0.1 cm 1 . The method is based on the application of a Fabry-Pérot interferometer to the spectral analysis of a broadband (BB) CARS spectral line profile with detection of an interference pattern by a linear charge-coupled device (CCD) detector.…”

“…Possible alternatives to static vessel measurements are hydrogen Raman linewidth measurements directly in a hydrogen-oxygen burner where continuous refreshment of the medium takes place. In a previous paper, 4 we reported on measurements of high-temperature collisional broadening coefficients of various H 2 Q-branch lines broadened by water molecules that have been performed in a pulsed high-pressure H 2 -O 2 burner. The values of H 2 Q 1 , Q 3 , Q 5 and Q 7 collisional broadening coefficients measured in our experiments 4 at 2700 K coincide within the experimental error with the values extrapolated from the values measured at 1800 K in a heated cell filled with H 2 and water vapor.…”

Non-intrusive gas-phase thermometry for industrial oxy-fuel burners

“…Several studies of different types of flames have proven its high capability [15][16][17][18]. Today, the CARS technique using the N 2 molecule as a temperature indicator is routinely used even in harsh combustion environments such as IC engines, high-pressure burners and gas turbines [19][20][21][22][23][24]. In order to probe temperatures in a technical relevant combustion chamber, optical access is always restricted by the need for very small windows.…”