Yu.P.Ladikov, P.P.Rabotchi, O.K.Cheremnukh The effect of translational vibration and uniform rotation on the processes of heat transfer in substance melt at cristall growing by Bridgmen's method in conditions of microgravitation |
Applied hydromechanics, Vol. 9 (81) ¹ 1, (2007) |
| In conditions of space flight convection caused by action of gravitational forces, owing to smallness the last, practically is absent. First, an opportunity of obtaining onboard space vehicles (SV) more homogeneous and perfect monocrystals than in terrestrial conditions (where gravitational convection renders essential influence on processes of crystallization) was associated with this fact. However, till now to receive the homogeneous and perfect crystals in such a way was not succeeded because of influence on experimental samples of various uncontrollable vibrations caused by work of SV. Such vibrating influences result in occurrence of convectional flows exerting essential influence on processes of heat and mass transfer in melts of substances. This can result in formation of inhomogeneities in structure of materials. In the given work the opportunity of weakening of influence of vibration on structure of a crystal material receiving in conditions of space experiment due to fast uniform rotation of an experimental sample is investigated. It is shown, that at presence of enough intensive uniform rotation vibration does not render essential influence on structure of convective flow in melt, which practically is determined by rotary motion. At the same time, such convective flow, according to the results received in work [7], practically does not interact with a crystallization front. This results in more homogeneous distribution of an impurity in crystal than in case of absence of rotation. |
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| TEXT LANGUAGE: Russian |