STP828

    Analysis of Droplet Spectra and Spray Recovery as a Function of Atomizer Type and Fluid Physical Properties

    Published: Jan 1983


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    Abstract

    Drop size, as indicated by the volume median diameter (VMD), and size uniformity, noted by the relative span (RS), were correlated with (1) viscosity, (2) surface tension, (3) viscoelasticity, and also (4) liquid throughput. Two types of nozzles were used, simple orifices or jets and hollow cones. The density of the mixtures did not vary greatly and no correlations were made with this function.

    Increased liquid throughput (increased orifice diameter) showed significant effects on drop size, increasing the VMD as the orifice size increased for all nozzles and mixtures tested. Of the liquid properties, viscoelasticity had the greatest effect, increasing drop size as it was increased. Increasing the surface tension increased drop size significantly, but changes in viscosity appeared to have little effect on the drop size produced.

    The RS was reduced (narrow range) as surface tension, viscosity, and viscoelasticity were increased. Increased throughput reduced RS at two surface tension levels, but when the viscoelastic polymer was used, the increased throughput actually increased the RS for the nozzles tested.

    The atomization process is very complex and the study using kromkote paper collection cards could have benefited significantly if the new Particle Measuring Systems Co. (PMS) in situ system had been available. Nonetheless, the data have considerable relevance to pesticide spray atomization. Further advances will be made as the PMS or similar scanners become more widely available.

    Keywords:

    pesticides, droplet spectra, spray recovery, liquid atomization, fluid physical properties


    Author Information:

    Haq, K
    Head, Rice Research Institute, Dacca,

    Akesson, NB
    Professors of agricultural engineering, University of California, Davis, Calif.

    Yates, WE
    Professors of agricultural engineering, University of California, Davis, Calif.


    Paper ID: STP32485S

    Committee/Subcommittee: E35.22

    DOI: 10.1520/STP32485S


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