Spontaneous Raman Scattering Measurements and CFD Simulations of Major Species and Temperature in a Turbulent Dilute Hydrogen Diffusion Flame

Dilute hydrogen diffusion flames represent a possible practical configuration for achieving extremely low emission of Nitric Oxides (NOx), and provide a challenging computational problem due to their complex turbulence-chemistry interactions and molecular transport effects. Experimental measurements of spatially resolved major species concentration and temperature were made in a hydrogen dilute diffusion flame using Spontaneous Raman Scattering, providing insight into the physical mechanisms leading to reductions in NOx and data for computational validation. Results from a computational model using Large Eddy Simulation (LES) were able to correctly predict several important flame features, such as the importance of differential diffusion effects in flame anchoring. Depressed flame temperatures were measured, resulting from the highly strained flame environment, providing a supporting explanation for the low NOx levels reported for this type of flame in the literature. The complex mechanisms governing the behavior of this flame make it an interesting target for computational validation.