A New Multicomponent Diffusion Formulation for the Finite-volume Method: Application to Convective Droplet Combustion

A new multicomponent formulation, appropriate for use with the finite-volume method, has been developed to describe mass diffusion velocities accurately. The new formulation is applied in a quasi-steady numerical model for n-heptane fuel droplet combustion in a forced-convection environment. Results obtained using the complete formulation are compared to the results obtained under various assumptions. Using a single binary diffusion coefficient produces results for extinction velocity, maximum temperature, flame dimensions , evaporation constant, and drag coefficient that are significantly different from the results obtained using the complete formulation. Neglecting thermal diffusion (Soret effect) causes only minor changes (less than 2%).