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Simulation of fluid flows during growth of organic crystals in microgravitySeveral counter diffusion type crystal growth experiments were conducted in space. Improvements in crystal size and quality are attributed to reduced natural convection in the microgravity environment. One series of experiments called DMOS (Diffusive Mixing of Organic Solutions) was designed and conducted by researchers at the 3M Corporation and flown by NASA on the space shuttle. Since only limited information about the mixing process is available from the space experiments, a series of ground based experiments was conducted to further investigate the fluid dynamics within the DMOS crystal growth cell. Solutions with density differences in the range of 10 to the -7 to 10 to the -4 power g/cc were used to simulate microgravity conditions. The small density differences were obtained by mixing D2O and H2O. Methylene blue dye was used to enhance flow visualization. The extent of mixing was measured photometrically using the 662 nm absorbance peak of the dye. Results indicate that extensive mixing by natural convection can occur even under microgravity conditions. This is qualitatively consistent with results of a simple scaling analysis. Quantitave results are in close agreement with ongoing computational modeling analysis.
Document ID
19870006734
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Roberts, Gary D.
(NASA Lewis Research Center Cleveland, OH, United States)
Sutter, James K.
(NASA Lewis Research Center Cleveland, OH, United States)
Balasubramaniam, R.
(NASA Lewis Research Center Cleveland, OH, United States)
Fowlis, William K.
(NASA Marshall Space Flight Center Huntsville, Ala., United States)
Radcliffe, M. D.
(Minnesota Mining and Mfg. Co. St. Paul, United States)
Drake, M. C.
(NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
September 5, 2013
Publication Date
January 1, 1987
Subject Category
Materials Processing
Report/Patent Number
NAS 1.15:88921
NASA-TM-88921
E-3354
Accession Number
87N16167
Funding Number(s)
PROJECT: RTOP 674-25-05
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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