Development of Combined Dual-Pump Vibrational and Pure-Rotational Coherent Anti-Stokes Raman Scattering (DPVCARS and PRCARS) System

Abstract

Coherent anti-Stokes Raman scattering (CARS) [1,2] is a spatially-resolved, time-resolved spectroscopic technique for quantitative measurements in reacting flows [3-6]. This work demonstrates a combination of N 2 /O 2 /CO 2 dual-pump vibrational coherent anti-Stokes Raman scattering (DPVCARS) system and two-beam pure-rotational coherent anti-Stokes Raman scattering (PRCARS) system. It is based on the previous development of combined VCARS and PRCARS system which was used to obtain temperature measurements in non-premixed H 2-air flames. The new combined system will be used to measure the temperature profiles and major species concentrations such as N 2 /O 2 /CO 2 in laminar counter-flow non-premixed (CH 4 /Air) and partiallypremixed (CH 4 /H 2 /Air) flames. The new system is being characterized in H 2 /Air diffusion flames stabilized over a Hencken burner. CO 2 will be added to the oxidizer stream for the system to assess the precision of the system while performing concentration measurements. The new combined system has shown good precision temperature using PRCARS (better than 3%) and N 2 /O 2 mole-fraction ratio (better than 5%) using DPVCARS.