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Sizing of microdrops

Authors :
Valerie Halyo
Sewan Fan
Howard Rogers
Peter C. Kim
Irwin T. Lee
Martin L. Perl
Eric R. Lee
Source :
Review of Scientific Instruments. 75:891-895
Publication Year :
2004
Publisher :
AIP Publishing, 2004.

Abstract

Several techniques for determining the size of small fluid microdrops with diameters ranging from 5 to 30 μm have been developed and evaluated using an automated variation on the Millikan oil drop experiment. The average diameter of a large sample of monodisperse fluid drops was determined by measuring their terminal velocity in air, or if charged, their motion under the influence of an electric field, as well as by measurement of the magnitude of their Brownian motion. The diameter of individual drops was determined optically, by direct observation using an imaging system based on a charge-coupled-device camera. The technique used to analyze the image data is based on a best-fit technique taking the point spread function of the lens into account, and yields results accurate to 1% (based on a single image) without the need for any calibration. By combining this technique with terminal velocity measurements, the density of the fluid can be determined to similar accuracy.

Details

ISSN :
10897623 and 00346748
Volume :
75
Database :
OpenAIRE
Journal :
Review of Scientific Instruments
Accession number :
edsair.doi...........cc24705399837ffe5db0a50b9c133cf3