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MOBI: Microgravity Observations of Bubble InteractionsOne of the greatest uncertainties affecting the design of multiphase flow technologies for space exploration is the spatial distribution of phases that will arise in microgravity or reduced gravity. On Earth, buoyancy-driven motion predominates whereas the shearing of the bubble suspension controls its behavior in microgravity. We are conducting a series of ground-based experiments and a flight experiment spanning the full range of ratios of buoyancy to shear. These include: (1) bubbles rising in a quiescent liquid in a vertical channel; (2) weak shear flow induced by slightly inclining the channel; (3) moderate shear flow in a terrestrial vertical pipe flow; and (4) shearing of a bubble suspension in a cylindrical Couette cell in microgravity. We consider nearly monodisperse suspensions of 1 to 1.8 mm diameter bubbles in aqueous electrolyte solutions. The liquid velocity disturbance produced by bubbles in this size range can often be described using an inviscid analysis. Electrolytic solutions lead to hydrophilic repulsion forces that stabilize the bubble suspension without causing Marangoni stresses. We will discuss the mechanisms that control the flow behavior and phase distribution in the ground-based experiments and speculate on the factors that may influence the suspension flow and bubble volume fraction distribution in the flight experiment.
Document ID
20040142377
Acquisition Source
Glenn Research Center
Document Type
Conference Paper
Authors
Koch, Donald L.
(Cornell Univ. NY, United States)
Sangani, Ashok
(Syracuse Univ. NY, 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: Presentations, Volume 1
Subject Category
Fluid Mechanics And Thermodynamics
Funding Number(s)
CONTRACT_GRANT: NAG3-1853
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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