STM Journals Peer-reviewed research from Consortium e-Learning Network

Journal of Aerospace Engineering & Technology

Theoretical and Experimental Research of Phenomena Arising in a Vessel Containing the Bubbles Dissolved in the Fluid and the Air above Surface of Fluid under Impact of Vibration in the Acoustic Range both in the Terrestrial and Decreasing Acceleration of Gravity Conditions

  1. Michael Shoikhedbrod

Abstract

Under terrestrial conditions, gravitational forces prevent to obtain materials that are homogeneous in distribution components and phases. Strong thermo gravitational unsteady convection leads to instability of crystals growth parameters and limits the possibilities of obtaining the crystals with a high degree of homogeneity and perfect parity structures. The first results of crystals growth in microgravity showed the fundamental possibility of producing more advanced crystals due to the absence of gravitational convection However, under microgravity conditions in melts, new opportunities for convective processes of non-gravitational type appear - Marangoni convection, as well as (in the presence of residual gravity) small thermo gravitational processes under gravity level decrease, which lead to the problem of obtaining perfectly homogeneous crystals. Another problem is the presence, in contrast to terrestrial conditions, of gas inclusions in melts and crystalline solutions, which also leads to impossibility of obtaining perfectly homogeneous crystals. The paper presents the ways to solve these problems by using controlled vibration for mixing of components of melts and concentrates, their degassing in the process of crystals growth in space flight.
Support