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Effects of Gravity on Bubble Formation in an Annular JetThe effects of gravity on the bubble formation in an annular jet were studied. The experiments were conducted in the 2.2-second drop tower at the NASA Glenn Research Center. Terrestrial gravity experiments were conducted at the Fluid Dynamics Research Laboratory at the University of Oklahoma. Stainless steel tubing with inner diameters of 1/8" (gas inner annulus) and 5/16" (liquid outer annulus) served as the injector. A rectangular test section, 6" x 6" x 14" tall, made out of half-inch thick Lexan was used. Images of the annular jet were acquired using a high-speed camera. The effects of gravity and varying liquid and gas flow rates on bubble size, wavelength, and breakup length were documented. In general, the bubble diameter was found to be larger in terrestrial gravity than in microgravity for varying Weber numbers (0.05 - 0.16 and 5 - 11) and liquid flow rates (1.5 ft/s - 3.0 ft/s). The wavelength was found to be larger in terrestrial gravity than in microgravity, but remained constant for varying Weber numbers. For low Weber numbers (0.05 - 0.16), the breakup length in microgravity was significantly higher than in terrestrial gravity. Comparison with linear stability analysis showed estimated bubble sizes within 9% of experimental bubble sizes. Bubble size compared to other terrestrial gravity experiments with same flow conditions showed distinct differences in bubble size, which displayed the importance of injector geometry on bubble formation.
Document ID
20040161197
Acquisition Source
Glenn Research Center
Document Type
Conference Paper
Authors
Koepp, R. A.
(Oklahoma Univ. Norman, OK, United States)
Parthasarathy, R. N.
(Oklahoma Univ. Norman, OK, United States)
Gollahalli, S. R.
(Oklahoma Univ. Norman, OK, United States)
Date Acquired
September 7, 2013
Publication Date
August 1, 2004
Publication Information
Publication: Strategic Research to Enable NASA's Exploration Missions Conference and Workshop: Poster Session, Volume 2
Subject Category
Fluid Mechanics And Thermodynamics
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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