NH₃/H₂/N₂ Counterflow Diffusion Flame Investigation Using Dual-pump Coherent Anti-Stokes Raman Scattering (DPCARS) Spectroscopy

<p dir="ltr">Temperature and X_H₂ /X_N2 concentration ratios of non-premixed fuel consisting of H₂,N₂, NH₃ and air within a counterflow diffusion burner using dual-pump coherent anti-Stokes Raman scattering (DPCARS) spectroscopy are reported. Fuel compositions range in concentration of NH₃ and flame strain rate. Good agreement is achieved between experimentally measured temperature and the results of 1-D numerical simulations that utilize four different chemical kinetics simulations, Okafor 2018, Stagni 2023, Glarborg 2023, and Manna 2023. Poor agreement between X_H₂ /X_N2 measurements and simulations is the result of temperature sensitivity to the pure-rotational H₂ S(5) spectral line. The DPCARS system was reconfigured for a less temperature sensitive H₂ S(2) spectral line and furthermore to a higher populated H₂ S(3) line. Better agreement between X_H2 /X_N2 measurements and simulations occurred with the H₂ S(3) line. Future work includes measurements with the newly reconfigured system with additional flames of increased NH₃ concentration and strain rates.</p>