Design and Numerical Study of Argon Gas Diversion System Using Orthogonal Experiment to Reduce Impurities in Large-Sized Casting Silicon

Abstract

To reduce oxygen and carbon impurities while casting silicon, an argon gas diversion system is proposed. A series of two-dimensional global transient numerical simulations are carried out using Fluent software according to the orthogonal experimental design, including heat transfer, convection of silicon melt and argon gas, and the fully coupling transport of impurities. The numerical results show that when the distance between the outer tube outlet and the cover is 10 mm, the backflow is inhibited by lateral outflow, thus the generation of CO is suppressed and the penetration of impurities into the silicon melt is decreased. The larger the flow rate, the more obvious the effect is. When the outer tube outlet is far from the cover, the effect of removing impurities is no longer significant. In addition, too large or too small an inner tube flow rate is not conducive to impurity reduction. The optimal parameter combination of outer tube flow rate, inner tube flow rate, and the distance between outer tube outlet and the cover are determined by the orthogonal experiment. Compared with the original furnace, the average concentration of oxygen and carbon in casting silicon ingots could be decreased by 7.4% and 59.9%, respectively, by using the optimized argon gas diversion system.

Numerical Analysis of the Influence of Size Upgrading on Oxygen and Carbon Impurities in Casting Silicon

“…In this paper, the twodimensional transient global models of G6 and G7 DS furnaces considering thermal convection, thermal radiation, melt and argon ow, phase transition, and impurities coupled transport were established. The differences between the G6 and G7 DS furnaces and the veri cations of the models can refer to in our published papers [10,12,21,23,24]. As shown in Fig.…”

“…The numbers of the grids are 34,248 (G6) and 42,994 (G7), respectively. The boundary conditions and transport equations for the transport of O and C impurities as well as material parameters refer to our published articles [10,12,21,23,24].…”