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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

1992, Volume2

126 pages

Issue price - $75.00

ATOMIZATION, CHARGE, AND DEPOSITION CHARACTERISTICS OF BIPOLARLY CHARGED AIRCRAFT SPRAYS

Kenneth D. Kihm
Texas A&M University College Station, TX; and Micro/Nano-Scale Fluidics and Energy Transport Laboratory, University of Tennessee, Mechanical, Aerospace and Biomedical Engineering Department, Knoxville TN 37996-2210, USA

B. H. Kim
Department of Mechanical Engineering, Texas A&M University, College Station, Texas 77843

A. R. McFarland
Department of Mechanical Engineering, Texas A&M University, College Station, Texas 77843

ABSTRACT

Atomization, charge, and deposition characteristics of a bipolar-charged electrostatic aircraft spray system were studied. The system used serrated spinner cup atomizers with tap water as the atomized fluid. Despite the well-known advantages of electrostatic sprays, electrical discharge from excessive buildup of residual charge on the aircraft skin has been a major problem in utilizing electrostatic systems for aircraft spraying. The idea of bipolar electrostatic charging has been investigated, and the results show that the bipolar charging could effectively abate the residual charge buildup. In addition, the deposition efficiency of aircraft sprays could be fairly significantly enhanced, Atomization and charging behaviors of the atomizer were studied under a laboratory simulation using a laser diffraction droplet sizing technique and a Faraday cage collector, respectively. The deposition characteristics were investigated by carrying out a field experiment with an aircraft spray system and a water-sensitive dye paper sampling technique. Droplet patterns on exposed dye papers were digitized and processed to obtain the droplet diameters and other statistical data. Compared with corresponding electrically neutral sprays, the average SMD of bipolar-charged sprays was increased by over 10%, with a noticeable decrease in the number of small droplets and an increase in large drops. The effect should reduce the drift problem of aircraft sprays. The total deposition mass was also increased by more than 45% when the spray was charged with dual polarities.