On simulations investigating droplet diameter-charge distributions in electrostatically atomized dielectric liquid sprays
A general procedure has been developed for the simulation of charged liquid and electrostatically atomized sprays. The procedure follows a Lagrangian approach for simulation of spray droplets and a Eulerian approach for gas-phase variables, including the electric field generated by the charge presence on droplets. Validation of the procedure was examined through simulations of previously published charged spray experiments. Results showed that for the specification of initial droplet charge, modelling the droplet charge-diameter relationship through a scaling law is as reliable a method as using a directly obtained charge-diameter relationship from experimental measurements. The normalized root-mean-square errors for sprays using the two methods were shown to be within 12% of one another, for the prediction of spatially averaged profiles of mean droplet diameters, mean axial velocities and mean radial droplet velocities. Results showed that the general spatial characteristics and dynamics of a charged liquid spray can successfully be reproduced, including the axial and radial dispersal pattern of droplets and the distribution of mean droplet diameters throughout the spray plume. For all sprays with droplet charges defined through a scaling law relationship, the normalized root-mean-square errors range from 9.0% to 31.6% for mean droplet diameters, 10.4% to 67.9% for mean axial droplet velocities and 16.8% to 38.6% for mean radial droplet velocities. Lastly, we present a brief set of general recommendations for simulating electrostatically atomized dielectric liquid sprays.Copyright (c) 2013 John Wiley & Sons, Ltd.
electrostatic atomization charged sprays charge injection cfd