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Viscosity Measurement using Drop Coalescence in MicrogravityWe present in here details of a new method, using drop coalescence, for application in microgravity environment for determining the viscosity of highly viscous undercooled liquids. The method has the advantage of eliminating heterogeneous nucleation at container walls caused by crystallization of undercooled liquids during processing. Also, due to the rapidity of the measurement, homogeneous nucleation would be avoided. The technique relies on both a highly accurate solution to the Navier-Stokes equations as well as on data gathered from experiments conducted in near zero gravity environment. The liquid viscosity is determined by allowing the computed free surface shape relaxation time to be adjusted in response to the measured free surface velocity of two coalescing drops. Results are presented from two validation experiments of the method which were conducted recently on board the NASA KC-135 aircraft. In these tests the viscosity of a highly viscous liquid, such as glycerine at different temperatures, was determined to reasonable accuracy using the liquid coalescence method. The experiments measured the free surface velocity of two glycerine drops coalescing under the action of surface tension alone in low gravity environment using high speed photography. The free surface velocity was then compared with the computed values obtained from different viscosity values. The results of these experiments were found to agree reasonably well with the calculated values.
Document ID
19990106577
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
Antar, Basil N.
(Tennessee Univ. Space Inst. Tullahoma, TN United States)
Ethridge, Edwin
(NASA Marshall Space Flight Center Huntsville, AL United States)
Maxwell, Daniel
(Tennessee Univ. Space Inst. Tullahoma, TN United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1999
Subject Category
Materials Processing
Meeting Information
Meeting: Annual Microgravity Science and Space Symposium
Location: Reno, NV
Country: United States
Start Date: January 13, 2000
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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