MODELING OF MULTIPLE VAPORIZING DROPLET STREAMS IN CLOSE SPACING CONFIGURATIONS

A model of convective droplet evaporation dynamics is presented for dr oplet-array configurations that feature close spacing. Comparisons wit h available experimental data on single and multiple ethanol droplet s treams show good agreement. Evidence is presented that evaporative coo ling of ethanol microdroplets is not negligible at room temperature. I t is shown that local vapor accumulation in the wake of the leading dr oplets plays an important role in depressing the evaporation rates of the trailing droplets. The influence of ambient blowing in a direction perpendicular to the path of droplet propagation is shown to be impor tant for the trailing droplets in situations where the evaporative flu x and the cross-stream convective flux carrying the fuel vapor away ar e of comparable magnitude. Model predictions for a densely arranged, o rdered spray system at elevated temperature and pressure suggest that in most cases the droplets approach one another, and there exist subst antial differences in evaporation characteristics between the core and the periphery of the spray. Initial droplet spacings of the order of a few droplet diameters are found to cause vapor spatial distributions which suggest that if ignition occurred, droplets would burn in group s more likely.