Effect of inter-particle interactions on evaporation of droplets in a linear array

Effects of interparticle interactions on evaporation have been examined on droplets in a linear array generated by a modified vibrating orifice aerosol generator (VOAG). The size as well as the spacing between the droplets was varied by modulating the frequency of the generator, and the liquid flow rate through the orifice. Ethanol and methanol droplets of differing initial sizes and spacings were studied, and the instantaneous evaporation rates as well as droplet temperatures were measured using a resonance-based light scattering technique. The results show that at a fixed dimensionless spacing between the droplets (i.e., the ratio of the spacing to the droplet radius, l/a), the size and temperature versus time data are highly reproducible. The measured evaporation rates were normalized by the evaporation rates of an isolated droplet under identical conditions to obtain the interaction parameter (η) as a function of the dimensionless spacing between the droplets. The value of η was observed to decrease with a decrease in l/a as predicted by the theoretical models, and as expected, found to be the same for ethanol and methanol droplets.