ISSN:
0001-1541
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Atomization experiments, motivated by the need to suppress misting of machining oils, were conducted on dilute solutions of polyisobutylene (PIB) in mineral oil using a coaxial air blast atomizer and an optical (Fraunhofer diffraction) particle sizer. Polymer concentrations (0.1 to 1.0 kg/m3) and molecular weight (1.0 to 2.2 million) were varied to determine their effects on aerosol drop-size distributions. The pure oil and PIB - oil solutions were atomized at air/liquid mass ratios near 10 and atomizing air velocities of 150-270 m/s, producing droplet-size distributions with mass mean diameters (MMD) in the range of 7-15 μm for the pure oil. Under identical atomization conditions, the MMDs of PIB solutions were 20-200% higher than pure oil. These observed increases in MMD correspond to significant reductions in the fraction of droplets falling below 5 μm in diameter that constitute the misting problem in industrial machining applications. Observed effects of PIB on atomization are ascribed to the viscoelastic properties of PIB - oil solutions as characterized by the elongational viscosity ηE. This relationship is examined by correlating the change in MMD caused by PIB addition with the stress-dependent elongational viscosity of PIB-oil solutions as predicted by the FENE-P dumbbell kinetic theory. The increase in MMD due to PIB varies linearly with the predicted ηE at constant atomization tensile stress.
Additional Material:
15 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/aic.690420502
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