Evaporation and coalescence of spray droplets comprised of two-component fuels

The evolution of spray mass distribution of two-component fuel droplets is described. Various evaporation rates and mass fractions within the initial droplet mass distinguish between the fuel components. A Lagrangian General Dynamic Equation for multicompnent droplets is employed where the focus here is on evaporation and droplet coalescence. The model employed enables calculating the cumulative evaporated mass of each individual fuel component. It is shown how evaporation alone, and a combination of evaporation and coalescence affect each individual fuel component, in addition to the effect on the total mass of the spray. Evaporation tends to increase the concentration of the slower evaporating component in the smaller size droplets, while coalescence opposes this trend. It is shown that the relative effect of simultaneous evaporation and coalescence on the mass of droplet fuel components depends on their evaporation rate as well as on their relative concentrations in the liquid phase.