TRANSITION-FLOW MODES IN CZOCHRALSKI CONVECTION

A laboratory experiment of critical transition flow modes in Czochrals ki convection was performed, Numerical computation was also made to de lineate the dynamic transition mechanism of flow modes. The period of temperature oscillation (t(p)) and the interval of temperature oscilla tion (Delta theta) were scrutinized to capture the critical transition regime. The mixed convection parameter was varied in a range 0.134 le ss than or equal to Ra/PrRe2 less than or equal to 3.804. The computed results were shown to be in good agreement with the experimental data . The influence of the Prandtl number on the transition was examined f or Pr = 910, 4445 and 8889. To understand the transition mechanism, th e detailed temperature oscillation modes, the isolines of meridional t emperature and the axial velocity profiles were investigated. The effe ct of the rotations of crucible on the transient flow modes were also examined.