A Review of the Effects of Droplet Size and Flow Rate on the Chargeability of Spray Droplets in Electrostatic Agricultural Sprays

Abstract

Abstract. The chargeability of liquid sprays is an important factor in determining the deposition efficiency of electrostatic pesticide sprays. The Rayleigh limit provides information on the maximum amount of charge a spray droplet can carry as a function of droplet size and liquid properties. This article reviews the literature to determine what fraction of the Rayleigh limit is achievable. Typically, less than 10% of the Rayleigh limit charge is obtained. The droplet charge per unit mass decreases with increasing droplet size and liquid flow rate. A correlation equation is derived from published data to predict spray droplet charge per unit mass from droplet size, flow rate, and charging voltage. Keywords: Droplet size, Electrostatic charging, Spray drift, Sprayers, Ultra-low volume spraying.