Modeling of spontaneous Raman scattering for detonation wave imaging

Abstract

To determine if spontaneous Raman scattering can be employed to perform temperature measurements in detonation waves propagating in a stoichiometric hydrogen–air mixture, a detailed rotational–vibrational Raman scattering model for nitrogen has been implemented. The Raman scattering cross-sections were calculated over the wavelength range 337–532 nm and show reasonable agreement with experimental data. The Raman model was coupled to steady one-dimensional and unsteady two-dimensional simulations of detonation to determine under which conditions temperature measurement can be performed with an appropriate signal-to-noise ratio. Based on the calculated Raman signal and signal-to-noise ratio fields, it was concluded that, through an integrated intensity ratio of Stokes Raman scattering and anti-Stokes Raman scattering, the Raman scattering temperature measurement might be possible for large incident laser light intensity and minimized background emission noise.