A Turbulence Model of Bi-Component Fuel Droplet for Atomizing Sprays

A new approach to account for simultaneously finite thermal conductivity, finite mass diffusivity and turbulence effects within atomizing liquid sprays is presented in this paper. The main contribution of this paper is to incorporate the liquid turbulence effect in modeling the multi-component droplet liquid jet evaporation. For this study, we consider a binary mixture of heptane and decane liquid fuel injected into a hot gas environment. The finite conductivity model is based on a newly developed two-temperature two-layer film theory of Chen et al. [1], where the turbulence characteristics of the droplet are used to estimate the effective thermal conductivity. Fuel droplets inherit turbulence from high Reynolds number issuing liquid injector flows. The present paper extends the formulation of Chen et al. [1] to estimate effective mass transfer diffusivity within the drop. In this model four regions are considered, interior and the surface of the droplet, the liquid gas interface and the surrounding gas phase. An approximate solution to the quasi-steady energy equation was used to derive an explicit expression for the heat flux from the surrounding gas to the droplet–gas interface, with inter-diffusion of fuel vapor and the surrounding gas taken into account. The thermo-transport properties including their dependence on temperature are considered. Validation studies were carried out by comparison with the experimental results.