Effect of pool rotation on flow pattern transition of silicon melt thermocapillary flow in a slowly rotating shallow annular pool

Autor: Nobuyuki Imaishi, You-Rong Li, Lan Xiao, Shuang-Ying Wu
Rok vydání: 2008
Předmět:
Zdroj: International Journal of Heat and Mass Transfer. 51:1810-1817
ISSN: 0017-9310
DOI: 10.1016/j.ijheatmasstransfer.2007.06.029
Popis: In order to understand the mechanism of the flow pattern transitions on silicon melt in Czochralski furnaces, we conducted a series of unsteady three-dimensional numerical simulations of silicon melt flow in a slowly rotating shallow annular pool in the counter-clockwise direction. The pool was heated from the outer cylinder and cooled at the inner cylinder. The temperature differences between the vertical outer and inner cylinders ranged from 5 K to 28 K and annular pool rotation rate from 0 and 2 rpm. Bottom and top surfaces of the melt pool were adiabatic. The simulation results indicate that two flow transitions occur when increasing the radial temperature difference along the free surface. At first, the steady two-dimensional flow becomes the first hydrothermal wave and then the second hydrothermal wave with less wave number. The critical conditions for the onset of the instability and the transition zone between the first and the second hydrothermal wave are determined at various rotation rates. Characteristics of the steady and the three-dimensional flows are discussed.
Databáze: OpenAIRE