The fluid surface shape and capillary phenomena under lowered gravity or weightlessness with application to space materials science (powder metallurgy technology: impregnation, liquid-phase sintering; welding, brazing)
|1Naidich, Yu.V, 1Gab, II, 2Evdokimov, VA, 2Kurkova, DI, 1Stetsyuk, TV, 2Grigorenko, NF, 2Chemigovtsev, EP, 2Zhuravlev, VS, 2Krasovsky, VP |
1Frantsevich Institute for Problems of Materials Science, National Academy of Sciences of Ukraine, Kyiv, Ukraine
2Frantsevich Institute for Problems of Materials Science, National Academy of Sciences of Ukraine, Kyiv, Ukraine
|Kosm. nauka tehnol. 2004, 10 ;(2-3):059-067|
|Section: Space Materials and Technologies|
|Publication Language: Ukrainian|
Some capillary phenomena, shapes of surfaces and menisci of liquids, wetting processes under lowered or zero value of earth gravitation acceleration (weightlessness) are studied. Theoretically, on the basis of computer integration of classic capillarity equations using previously created programs and varying acceleration g values, and experimentally, modelling weightlessness on the Earth (using small volumes, namely drops of a liquid under lowered gravitation action, or creating interphase boundaries between nonmiscible liquids of equal density), the shape of liquid phases surface (for molten metals) are studied in most typical systems: a drop on a solid surface and liquid meniscus in a cylindrical channel. The experiments concerning to wetting contact angles dependence on gravitation discussed today were carried out (independence of wetting contact angle on value and direction of gravitation vector action is shown). The wetting contact angles in model systems are specially measured also at zero gravitational pressure, which is of basic importance for the theory of capillarity. The results are used in technology of materials brazing, powder metallurgy, in manufacturing of heat pipes porous capillary structures with an eye to implementation of these technologies in space environments (microgravitation).
|Keywords: space materials science, theory of capillarity, weightlessness|
1. Diakonov V. P. Handbook of algorithms and programs in the language BASIC for the personal computer, 240 p. (Nauka Publ., Moscow, 1987) [In Russian].
2. Naidich Yu.V. Contact Phenomena in Metal Melts, 196 p. (Naukova Dumka, Kiev, 1972) [In Russian].
3. Haynes J. Capillary phenomena in condition of microgravity. In: Space technology, Ed. by L. Steg, 55-63 (Mir, Moscow, 1980) [In Russian].
4. Bashforth F., Adams J. C. An attempt to test the theories of capillary action, 139 p. (Univ. Press, Cambridge, 1883).
5. Everet D. H., Haynes J. M. The Thermodynamics of Fluid Interfaces in a Porous of Medium Part. I. General Thermodynamic Considerations with Figures. Z. Phys. Chem., 82 (36), 36—48 (1972).
6. Frich B., Hargater E. Zur Randwinkelmessung des Liegenden Tropfens, dargestellt am System alpha-Aluminiumoxid-Queck-silber. Dtr. deutsch. Keram. Ges., 40 (8), P. 460 (1963).
7. Haynes J. M. Capillary instabilities in Ig and Og. Proc. of the Second European Symposium on Material Sciences in Space. European Space Agency. Special publ., N 114, 467—471 (1976).
8. Padday J. F. Capillary forces and Stability in Zero-gravity Environments. Proc. of the Second European Symposium on the Material Sciences in Space. European Space Agency. Special publ., N 114, 447—454 (1976).
9. Yixiong Liu, German R. M. Contact angle and solid-liquid-vapor equilibrium. Acta Mater., 44 (4), 1657—1663 (1996).
10. Young T. An Essay on the Cohesion of Fluids. Trans. Roy. Soc. London, 94, P. 65 (Read December 20, 1804) (1805).