Hydrogen CARS thermometry in a high-pressure H-2-air flame. Test of H-2 temperature accuracy and influence of line width by comparison with N(2)CARS as reference

This work describes a further step towards the determination of the tempera ture accuracy of H-2 Q-branch CARS (Coherent Anti-Stokes Raman Scattering) at high pressure with regard to the influence of the H2 line widths. In lam inar steady H-2/air flames in the pressure range 1-15 bar and at fuel-rich conditions with stoichiometries between two and four, quasi-simultaneous te mperature measurements were performed with H-2 and N-2 CARS. The temperatur e values deduced from H-2 CARS are in good agreement with the reference tem perature from N-2 CARS. The influence of different line-width contributions on the accuracy of H-2 Q-branch thermometry was investigated in detail.