NUMERICAL SIMULATION OF A STEADY HOLLOW-CONE METHANOL SPRAY FLAME WITHIN AN ANNULAR AIR JET

Abstract

ABSTRACT Numerical simulations are performed to investigate a reacting steady hollow-cone methanol spray interacting with an annular air jet. Eulerian conservation equations are solved for gas flow while a stochastic Lagrangian method is used for sprays in KIVA-3 (Amsden 1993). Initial conditions for injected droplet parcels are sampled stochastically from the distribution functions based on measured liquid volume flux and Sauter mean diameter. Coupling between turbulent flow and chemistry is treated by the conserved scalar approach with a beta function probability density function for the mixture fraction. Mean gas temperature, OH concentration, Sauter mean diameter, and liquid volume flux are in reasonable agreement with measurements for three different air flow rates. It is shown that the annular air jet tends to deflect droplets toward the axis, providing a narrower and shorter reaction zone suitable for a more compact combustion chamber. Discrepancy for the no air jet case is attributed to the isotropic turbulent dispersion model for droplet-eddy interaction. Other possible reasons may be the k − c model for gas flow, improper input conditions for injected droplet parcels, and inaccurate correlations for exchange of mass, momentum, and energy between droplets and gas.