Toward a Microgravity Research Strategy (1992) / Chapter Skim
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Appendix D: Fluids, Interfaces, and Transport
Appendix D: Fluids, Interfaces, and Transport
Pages 36-42
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From page 36... ...
REPORT MENU NOTICE These experiments and the supporting analyses of fluid and interfacial MEMBERSHIP processes have played a dominant role in past research programs, making this SUMMARY area one of the best-developed and best-documented fields of microgravity CHAPTER 1 research. Many review papers have appeared on aspects of this subject.
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From page 37... ...
Potential applications of these fundamental results, both on Earth and in space, are highlighted and key issues deserving future research are addressed. Fundamental studies in transport processes can be divided into two segments: research aimed at the analysis of the effects of coupled transport processes where each process is well understood individually, and research focused on understanding of fluxes of mass, heat, and species in complex systems, where present theory gives a less than adequate description.
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From page 38... ...
These observations spawned both theoretical studies and Earth based experiments that have demonstrated the importance of controlling very weak convective flows to obtain highly uniform solute concentrations in microgravity solidification systems. Removing the influence of convection also has uncovered the importance of secondary mechanisms for diffusive transport.
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From page 39... ...
Accordingly, microgravity studies of drop dynamics and coalescence have flourished and have found application as the basis for new measurement methods for liquid viscosity and surface tension. Experimental observations of drop dynamics made early in the NASA microgravity program and later results from Space Shuttle experiments spawned many high-quality, theoretical studies of the fluid mechanics of drops and bubbles and advanced this science considerably.
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From page 40... ...
The emphasis has been on the search for precise descriptions for the morphogenesis of the microstructure patterns, such as solidification cells and dendrites, that form as a function of changes in macroscopic operating conditions -- temperature gradient, growth rate, and alloy composition. The formation of these small-scale microstructures during phase change is ubiquitous, occurring not only in crystal growth from melts and solutions, but also in electroplating and phase changes in liquid crystal systems.
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From page 41... ...
Studies of mass and heat transfer in two-phase flow will also be important in understanding the effects of microgravity on the operation of classical heat transfer and separation technologies in a space environment. RESEARCH PROSPECTS AND OPPORTUNITIES Further progress in the fundamental understanding of transport processes and interfacial systems in microgravity will rely on the continued growth of theoretical and computational research and on expansion of the experimental database.
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From page 42... ...
Microgravity Science and Applications Division, National Aeronautics and Space Administration. Last update 7/13/00 at 3:51 pm file:///C|/SSB_old_web/cmgr92appendd.htm (7 of 8)
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