Controlled Production of Droplets by In-Flight Electrospraying

Abstract

Diameter, velocity, and charge measurements of progeny droplets produced in-flight by a millimeter-size parent drop subjected to electric and ionic fields are reported. Different drop breakup modes were studied using phase doppler anemometry and high-speed digital photography. Drop breakup occurred in applied electric (∼1 kV/cm to ∼10 kV/cm) and ionic (∼10(13)/m(3) to ∼10(15)/m(3)) fields that were generated using a DC-corona discharge in a needle-plate configuration. Effects of the external electric field and the diameter of the parent drop are considered. Several models are summarized, including simulations of the electrohydrodynamics of the corona discharge, electrocapillary stability analysis of the jet, and progeny droplets mobility analysis. Using experimental and model results, the charge of progeny drops is shown to vary as the three-halves power of their diameter.

Aerosol Generation by a Spray-Drying Technique Under Coulomb Explosion and Rapid Evaporation for the Preparation of Aerosol Particles for Inhalation Tests

“…We considered that the small aerosol particles were generated from small droplets by the breakup of the larger droplets that were lost because of inertial impaction on the flow path in the absence of breakup. As previously mentioned, a droplet is broken into one parent droplet and numerous small progeny droplets (Kim and Dunn 2010). The small droplets were aerosolized, whereas the parent droplet was not because of the inertial impaction.…”

“…Notably, the droplet is not divided equally. It is rather broken up partially, as shown in Figure 1, i.e., the droplet is broken into one droplet and numerous small progeny droplets (Kim and Dunn 2010). The aerosol particle generated from the small progeny droplets would be an individual primary nanoparticle or small agglomerate consisting of a small number of nanoparticles.…”

Investigation of a pilot-scale wet electrostatic precipitator for the control of sulfuric acid mist from a simulated WFGD system

“…In practice, studies indicate that the Rayleigh limit is not obeyed and drop break-up occurs already at charges below the Rayleigh limit (Taylor, 1964;Shrimpton, 2005;Kim and Dunn, 2010). Shrimpton (2005) revealed that in the presence of external electric field, the drop charge at break-up may only be 55-80% of the Rayleigh limit, which depends in some way on the material properties of drop.…”

“…However, taking into account of the inhomogeneity of the applied electric field and space charge effect inside WESP, the local charge of drop/aerosol may reach the sub-Rayleigh limit. Kim and Dunn (2010) studied the breakup of millimeter-sized drops in applied electric ( $ 1 kV/cm to $ 10 kV/cm) and ionic fields ( $ 10 13 /m 3 to $10 15 /m 3 ) that were generated using a DC-corona discharge in a needle-plate configuration, which indicated that a second generation of smaller progenies with submicron and nanometer size can also be produced when the applied voltage reached 44 kV. Also, the study revealed that in addition to electric field of corona discharge, the field of the strongly charged jet induces electric stresses, which also assists in destabilizing progenies.…”

Design and morphology control of a thiophene derivative through electrospraying using various solvents

“…7,8 Electrospraying is a technique to control and modify morphology with various controlling parameters such as solvents, solution concentration, applied voltage, tip to collector distance and flow rate. 7,8 Electrospraying is a technique to control and modify morphology with various controlling parameters such as solvents, solution concentration, applied voltage, tip to collector distance and flow rate.…”