Imaging measurements and LES-CMC modeling of a partially-premixed turbulent dimethyl ether/air jet flame

Abstract

Turbulent dimethyl ether (DME) jet flames provide a canonical flame geometry for studying turbulence-flame interactions in oxygenated fuels and for developing predictive models of these interactions. The development of accurate models for DME/air flames would establish a foundation for studies of more complex oxygenated fuels. We present a joint experimental and computational investigation of the velocity field and OH and CH2O distributions in a piloted, partially-premixed turbulent DME/air jet flame with a jet exit Reynolds number, Re-D, of 29,300. The turbulent DME/air flame is analogous to the well-studied, partially-premixed methane/air jet flame, Sandia Flame D, with identical stoichiometric mixture fraction, xi(st) = 0.35, and bulk jet exit velocity, V-bulk = 45.9 m/s. Measurements include particle image velocimetry (PIV) and simultaneous CH2O and OH laser-induced fluorescence (LIF) imaging. Simulations are performed using a large eddy simulation combined with conditional moment closure (LES-CMC) on an intermediate size grid of 1.3 million cells. Overall, the downstream evolution of the mean and RMS profiles of velocity, OH, and CH2O are well predicted, with the largest discrepancies occurring for CH2O at x/D = 20-25. LES-CMC simulations employing two different chemical rea