Single‐shot CARS thermometry of high‐pressure hydrocarbon flames using simultaneous intensity and linewidth measurements

We demonstrate the feasibility of single laser shot coherent anti‐Stokes Raman scattering thermometry with simultaneous measurement of intensities of hydrogen Q‐branch lines and their linewidths in a pulsed CH₄/O₂ combustion chamber operating at 20 MPa pressure and 3000 K temperature—parameters that are typical for full‐scale rocket engines. The measurements were done by means of a spectrograph combined with an interferometer having orthogonal directions of dispersions. This approach allows correct temperature evaluation that takes into account the directly measured linewidths. Copyright © 2010 John Wiley & Sons, Ltd.