Modeling droplet vaporization and combustion with the volume of fluid method at a small Reynolds number

The volume of fluid(VOF) formulation is applied to model the combustion process of a single droplet in a hightemperature convective air free stream environment.The calculations solve the flow field for both phases,and consider the droplet deformation based on an axisymmetrical model.The chemical reaction is modeled with one-step finite-rate mechanism and the thermo-physical properties for the gas mixture are species and temperature dependence.A mass transfer model applicable to the VOF calculations due to vaporization of the liquid phases is developed in consideration with the fluctuation of the liquid surface.The model is validated by examining the burning rate constants at different convective air temperatures,which accord well with experimental data of previous studies.Other phenomena from the simulations,such as the transient history of droplet deformation and flame structure,are also qualitatively accordant with the descriptions of other numerical results.However,a different droplet deformation mechanism for the low Reynolds number is explained compared with that for the high Reynolds number.The calculations verified the feasibility of the VOF computational fluid dynamics(CFD) formulation as well as the mass transfer model due to vaporization.

The volume of fluid （VOF） formulation is applied to model the combustion process of a single droplet in a high- temperature convective air free stream environment. The calculations solve the flow field for both phases, and consider the droplet deformation based on an axisymmetrical model. The chemical reaction is modeled with one-step finite-rate mechanism and the thermo-physic,! properties for the gas mixture are species and temperature dependence. A mass transfer model applicable to the VOF calculations due to vaporization of the liquid phases is developed in consideration with the fluctuation of the liquid surface. The model is validated by examining the burning rate constants at different convective air temperatures, which accord well with experimental data of previous studies. Other phenomena from the simulations, such as the transient history of droplet deformation and flame structure, are also qualitatively accordant with the descriptions of other numerical results. However, a different droplet deformation mechanism for the low Reynolds number is explained compared with that for the high Reynolds number. The cal- culations verified the feasibility of the VOF computational fluid dynamics （CFD） formulation as well as the mass transfer model due to vaporization.