DNS of n-heptane droplet vaporization and combustion

This paper presents fully resolved numerical simulations of droplet vaporization and combustion using a finite volume solver. The work was developed to study the influence of droplet vaporization on spray combustion phenomena. The flow solver is designed for simulating turbulent, multiphase flows under the low-Mach assumption. Simulations are performed on a Cartesian grid, and are able to track the freely deforming liquid droplets using a Volume of Fluid method. Transport of momentum and scalars is performed using an algorithm designed for liquid-gas flows with high density ratio. Vaporization is handled automatically based on the local requirements of mass and energy conservation at the interface and the requirement of thermodynamic equilibrium between the two phases. N-Heptane is chosen as the fuel because of its common use a fuel surrogate. Initial results are demonstrated for individual burning droplets in quiescent and uniform flows. These results are compared to classical correlations for the vaporization rate and flame stand off ratio. Finally, droplet-droplet interaction is studied through simulations of co-burning droplets.