Efficient atomization of brine at atmospheric pressure

An efficient and reliable technique to generate fine aerosols at atmospheric pressure is crucial in many engineering applications. Particularly, the development of a reliable continuous generation of fine aerosols from brine at atmospheric pressure is an essential step towards the future development of a portable thermal desalination system. In this study, we demonstrate the performance of a without-nozzle technique, which consists of a piezoelectric transducer coupled with a focusing tip, to rapidly destabilize the liquid-air interface, leading to the generation of fine aerosols. Unlike the conventional with-nozzle technique, which suffers a substantial decrease in aerosol generation rate after two hours of continuous operation, no significant change in aerosol generation rate in the without-nozzle technique. Nonetheless, increasing salt concentration in the solutions reduces the aerosol generation rate, which can be attributed to the increase in the surface tension, viscosity, as well as the density of the solutions. A reduction of aerosol generation rate of up to 60% when salt concentration is increased from 10% to 30%. Concomitantly, the aerosol size is also reduced at higher salt concentration. To further improve the efficiency of the technique, we also examine the effect of signal amplitude modulation and burst modulation. At a fixed power, up to 15% and 26% increase in aerosol generation rate can be obtained by using amplitude and burst modulation, respectively. For the amplitude modulation, the aerosol generation rate can be increased by increasing the modulation index, whereas, for the burst modulation, the aerosol generation can be increased when the number of trigger-cycle is larger than 60% of the number of total-cycle.