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Determination of the Accommodation Coefficient Using Vapor/gas Bubble Dynamics in an Acoustic FieldNonequilibrium liquid/vapor phase transformations can occur in superheated or subcooled liquids in fast processes such as in evaporation in a vacuum. The rate at which such a phase transformation occurs depends on the "condensation" or "accommodation" coefficient, Beta, which is a property of the interface. Existing measurement techniques for Beta are complex and expensive. The development of a relatively inexpensive and reliable technique for measurement of Beta for a wide range of substances and temperatures is of great practical importance. The dynamics of a bubble in an acoustic field strongly depends on the value of Beta. It is known that near the saturation temperature, small vapor bubbles grow under the action of an acoustic field due to "rectified heat transfer." This finding can be used as the basis for an effective measurement technique of Beta. We developed a theory of vapor bubble behavior in an isotropic acoustic wave and in a plane standing acoustic wave. A numerical code was developed which enables simulation of a variety of experimental situations and accurately takes into account slowly evolving temperature. A parametric study showed that the measurement of Beta can be made over a broad range of frequencies and bubble sizes. We found several interesting regimes and conditions which can be efficiently used for measurements of Beta. Measurements of Beta can be performed in both reduced and normal gravity environments.
Document ID
20010056682
Document Type
Contractor Report (CR)
Authors
Gumerov, Nail A. (DynaFlow, Inc. Fulton, MD United States)
Hsiao, Chao-Tsung (DynaFlow, Inc. Fulton, MD United States)
Goumilevski, Alexei G. (DynaFlow, Inc. Fulton, MD United States)
Allen, Jeff
Date Acquired
September 7, 2013
Publication Date
January 1, 2001
Subject Category
Fluid Mechanics and Thermodynamics
Report/Patent Number
E-12538
NASA/CR-2001-210572
NAS 1.26:210572
TR-98001
Funding Number(s)
CONTRACT_GRANT: NAS3-98094
PROJECT: RTOP 101-13-0A
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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