This paper investigates the effect of an ultrasound field on the evaporation of water droplets into an air stream flowing along a conduit. The air and droplet mixture (aerosol) is passed through an intense ultrasound field, generated in a cylindrical sonotrode, in an effort to accelerate the droplet evaporation process. The improvement in droplet evaporation was evaluated by measuring changes in the droplet size distribution and changes to the air humidity and temperature. It was found that at high power levels the droplets were rapidly and completely vaporized. At power levels in the 2 - 20 W range there was a significant increase in droplet evaporation, up to 28%, but also some droplet coalescence occurred. The mechanism for this improvement was thought to be a result of enhanced convection heat and mass transfer processes and the input of heat energy into the aerosol. This study has demonstrated that an ultrasound field does improve water droplet evaporation.
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