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Atomization and Sprays

Journal of the International Institutes for Liquid Atomization and Spray Systems

ISSN for PRINT: 1045-5110

Institutional price:	$787.00
Issues per year:	8

Best Paper Award Selection - Editorial Board Site

2005, Volume15

152 pages

Issue price - $92.00

ELECTROSTATIC EFFECTS ON AGRICULTURAL AIR-ATOMIZED SPRAYS AND DEPOSITION. PART II: A COMPUTATIONAL STUDY

M. R. Jahannama
Atomization and Sprays Research Group, Mechanical, Aeronautical and Manufacturing Engineering Department, UMIST, Manchester M60 1QD, UK

A. Paul Watkins
Atomization and Sprays Research Group, Department of Mechanical, Aerospace and Manufacturing Engineering, University of Manchester Institute of Science and Technology, Manchester, U.K.

Andrew J. Yule
Spray Research Group (SRG), Insititute of Materials Research (IMR), School of Computing, Science and Engineering, University of Salford, Manchester, UK

ABSTRACT

This article reports on a computational investigation of inductively charged sprays used in crop spraying. The charged sprays are produced using an air-atomizing induction-charging nozzle. In complementary research, the spray structures are experimentally characterized based on drop size and velocity data obtained using laser-based techniques, both in the free spray and in the near-target vicinity. The experimental deposition study used spectrophotometry analysis to quantify the drop residue on a grounded target. The study reported on here comprises the computational simulation of free spray and deposition aspects of charged and uncharged sprays, and uses the data obtained in the parallel investigation to determine the ability of the computational model to accurately predict such sprays. Experimental test results demonstrate the dominance of hydrodynamic effects within the charged free sprays, whereas, in the vicinity of a grounded target, the sprays are influenced by the attractive electrostatic force fields created, leading to greater drop depositions on the target than for an uncharged spray. These trends are confirmed by the computational results. However, there are differences of detail. The model generally underpredicts the effects of the electric fields on the spray motion near the target. This is probably due to an incorrect mass flux profile at the injector, leading to too little mass and, hence, charge being predicted in the target vicinity.