TEMPERATURE DISTRIBUTION AND MASS TRANSFER OF FLOW BY FREE CONVECTION IN ENCLOSURES.

The current study is motivated by crystal growing processes. Crystal growth in an enclosure is a global phenomenon which is difficult to control, due to the multiplicity of the particular phenomena involved: attack of the solid by liquid (gas) phase, convective and diffusive transport in this liquid (gas) phase, surface nucleation and growth kinetics. To obtain more perfect crystals, each of these phenomena must be understood and controlled, and in particular the hydrodynamic behavior of the parent phase (liquid or gas), as a function of the thermomechanical and geometrical data. The crystal growth rate in the transport process is usually limited by the mass transfer in the liquid (gas) phase rather than interface kinetics. The work presented herein is an experimental study of convective flows in shallow rectangular enclosures with the boundary conditions relevant to a crystal growing experiment. An electrochemical method is employed to impose both temperature and concentration gradients horizontally.