Characteristics and Parameterization of Spray Combustion in Laminar Counter-flow Jet Flames

摘要

A laminar counter-flow heptane (nC_7H_(16)) spray jet flame is investigated by the means of numerical methods. An Eulerian-Lagrangian method is used to solve the steady state gas phase and mono-dispersed fuel droplets in the simulation domain. Finite rate chemistry model with a reduced mechanism (88 species and 387 reactions) is used for combustion and a discrete particle method is used to solve the droplet dynamics. The numerical results are in reasonable agreement with the experimental data (M. Massot, M. Kumar, M.D. Smooke and A. Gomez, Proceedings of the Combustion Institute, vol. 27 (1998), 1975-1983). The focus of the study is placed on the parametric analysis of the effect of strain rate and droplet dynamics (droplet diameter and droplet mass loading) on the counter-flow spray flame. A conserved scalar named the mixing variable is defined to parametrize the laminar spray flame. Mixing variable is chosen over the traditional mixture fraction because of its monotonicity. The study gains insight into the effect of droplet dynamics on the flamelet structures and paves a basis for our future work on developing and employing flamelet models for turbulent spray combustion modeling.