Affiliations: Department of Mechanical Engineering, Indian Institute
of Technology, Kanpur, 208016, India | Department of Mechanical Engineering, SUNY Stony
Brook, New York, USA. E-mail: [email protected]
Abstract: Steady state temperature distribution in a model Czochralski
crucible has been mapped by liquid crystal thermography (LCT). The crucible is
a water-filled glass beaker. Water is used as the test fluid because of ease of
experimentation, as well as the availability of correct thermo-physical
properties. In addition, the Prandtl number of water matches those of molten
oxides. A copper cylinder whose diameter is smaller than that of the beaker is
placed centrally at the water surface. Convection patterns are set up by
applying constant temperature difference between the crucible wall and the
cylinder surface, in the temperature range of the liquid crystals. The cylinder
is given a fixed rotation, thus creating mixed convection conditions in the
test fluid. The LCT images recorded in the present study clearly reveal
convective rolls, and the interaction of buoyancy-driven convection in the
crucible with cylinder rotation. The resulting temperature distributions match
numerical simulation quite well. The pure buoyancy and pure rotation
experiments result in axisymmetric temperature fields, while in mixed
convection, the field is unsteady and three dimensional.
Keywords: Convection, Buoyancy, Rotation, LCT, Axisymmetry, Numerical model
