Effect of Argon Gas Flow on the Thermal Field in a Directional Solidification System for Multi-Crystalline Silicon

2013 ◽  
Vol 690-693 ◽  
pp. 945-948
Author(s):  
Xiang Rong Ma ◽  
Wu Zan ◽  
Xin Liang Zhang
Keyword(s):  
Heat Transfer ◽  
Free Surface ◽  
Directional Solidification ◽  
Gas Flow ◽  
Thermal Field ◽  
Crystalline Silicon ◽  
Casting Process ◽  
Argon Gas ◽  
Melt Convection

Directional Solidification System (DSS) is the commonly used casting station in the solar industry. In order to better understand the casting process, we carried out global simulations of heat transfer to investigate effect of argon gas flow on the thermal field in a directional solidification system for multi-crystalline silicon (mc-Si). The effect of argon gas flow on the global heat transfer and the melt convection are investigated. It was found that the heat transfer at the melt free surface due to the gas convection can not be neglected, though the argon gas flow contributes little to the global heat transfer at most radiative surfaces.

scholarly journals Effect of Argon Flow on Oxygen and Carbon Coupled Transport in an Industrial Directional Solidification Furnace for Crystalline Silicon Ingots

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 421
Author(s):  
Xiaofang Qi ◽  
Yiwen Xue ◽  
Wenjia Su ◽  
Wencheng Ma ◽  
Lijun Liu
Keyword(s):  
Directional Solidification ◽  
Flow Rate ◽  
Crystalline Silicon ◽  
Coupled Transport ◽  
Argon Flow Rate ◽  
Argon Gas ◽  
Argon Flow ◽  
Silicon Melt ◽  
Solidification Furnace ◽  
Evaporation Flux

Transient global simulations were carried out to investigate the effect of argon flow on oxygen and carbon coupled transport in an industrial directional solidification furnace for quasi-single crystalline silicon ingots. Global calculation of impurity transport in the argon gas and silicon melt was based on a fully coupled calculation of the thermal and flow fields. Numerical results show that the argon flow rate affects the flow intensity along the melt–gas surface, but has no significant effect on the flow patterns of silicon melt and argon gas above the melt–gas surface. It was found that the evaporation flux of SiO along the melt–gas surface decreases with the increasing argon flow rate during the solidification process. However, the net flux of oxygen atoms (SiO evaporation flux minus CO dissolution flux) away from the melt–gas surface increases with the increasing argon flow rate, leading to a decrease in the oxygen concentration in the grown ingot. The carbon concentration in the grown ingot shows an exponential decrease with the increase of the argon flow rate, owing to the fact that the dissolution flux of CO significantly decreases with the increasing argon flow rate. The numerical results agree well with the experimental measurements.

Temperature Distribution of Multi-Crystalline Silicon Ingots in the Directional Solidification Process

2013 ◽  
Vol 690-693 ◽  
pp. 977-980
Author(s):  
Xiang Rong Ma ◽  
Wu Zan ◽  
Xin Liang Zhang
Keyword(s):  
Temperature Distribution ◽  
Directional Solidification ◽  
Crystalline Silicon ◽  
Solidification Process ◽  
Casting Process ◽  
System Optimization ◽  
Silicon Melt ◽  
Solidification Furnace ◽  
Essential Knowledge ◽  
Melt Solidification

In order to better understand the casting process, we carried out global simulations of heat transfer to investigate the temperature distributions in furnace at 80 mm of insulation cage elevation and 40% of silicon melt solidification for multi-crystalline silicon (mc-Si) ingot using an industrial directional solidification furnace capable of producing 500 kg silicon ingot. The effect of heater position and the crystallization state of silicon melt on temperature distribution and interface shape are discussed as well to provide the essential knowledge for system optimization.

Temperature Field Analysis of Directional Solidification of Multi-Crystalline Silicon

2013 ◽  
Vol 750 ◽  
pp. 96-99 ◽  
Author(s):  
Yan Hu ◽  
Hai Hao ◽  
Xiao Teng Liu
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Solar Cells ◽  
Directional Solidification ◽  
Crystalline Silicon ◽  
Cost Effective ◽  
Field Analysis ◽  
Temperature Fields ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients

A cost effective directional solidification (DS) technique is one of the main methods to produce multi-crystalline silicon (mc-Si) ingots for solar cells. A detailed understanding of the DS process is very important to control the formation and distribution of impurities, precipitates, thermal stress and dislocation defects in an ingot. All these factors have direct effects on the solar cells efficiency. The quality of crystal grown by DS is largely determined by the temperature field. In order to optimize the technique parameters and obtain high quality silicon ingots, the temperature fields with different heat transfer coefficients at different positions have been calculated during the silicon DS process. The influence of the heat transfer coefficients at the ingot top(ht), the ingot bottom (hb), and between ingot and crucible (hs) on the DS process of mc-Si have been analyzed. The calculation results may provide important theoretical basis for optimizing technological recipe in the productive practice.

scholarly journals Analysis of the Effect of a Vertical Magnetic Field on Melt Convection and Oxygen Transport During Directional Solidification of Multi-Crystalline Silicon by Numerical Simulation

Crystals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 8
Author(s):  
Botao Song ◽  
Yufeng Luo ◽  
Senlin Rao ◽  
Fayun Zhang ◽  
Yun Hu
Keyword(s):  
Magnetic Field ◽  
Numerical Simulation ◽  
Directional Solidification ◽  
Oxygen Concentration ◽  
Crystalline Silicon ◽  
Vertical Magnetic Field ◽  
Silicon Melt ◽  
Average Oxygen Concentration ◽  
Melt Convection ◽  
The Magnetic Field

Melt convection during the directional solidification process of multi-crystalline silicon plays a critical role in the transport of impurities. The utilization of a static magnetic field is an effective way to control the melt convection pattern. Studying the effect of the Lorentz force induced by the vertical magnetic field (VMF) on the melt convection of silicon in detail is beneficial to optimize the magnetic field parameters in the production process. Based on the numerical simulation method of multi-physics coupling, this paper explores the effects of different VMF intensities on the convection of silicon melt and the transport of oxygen in the melt during the directional solidification of polycrystalline silicon. The results show that in the first 125 minutes of the crystallization stage, the melt convection velocity is affected significantly by the magnetic field intensities. When different convection circulations are present in the silicon melt, the upper circulation easily transports oxygen to the furnace atmosphere, and the subjacent circulation easily lead to the retention and accumulation of oxygen. Enhancing the VMF intensity to a certain extent can reduce the size of the oxygen retention region in the silicon melt, and the time of the first disappearance of the subjacent circulation near the sidewall of the crucible is shortened. Then the average oxygen concentration in the silicon melt can be reduced. However, a larger vertical magnetic field intensity can result in greater average oxygen concentration in the oxygen retention region.

Distributed Joule-Thomson effects and convective heat transfer of high-pressure argon gas flow in helically coiled mini-tubes

2020 ◽  
Vol 181 ◽  
pp. 115955
Author(s):  
Liang Chen ◽  
Jie Cai ◽  
Kunpeng Lv ◽  
Xue Yang ◽  
Shuangtao Chen ◽  
...  
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Gas Flow ◽  
Argon Gas
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