scholarly journals Preservation of Seed Crystals in Feedstock Melting for Cast Quasi-Single Crystalline Silicon Ingots

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Zaoyang Li ◽  
Lijun Liu ◽  
Yunfeng Zhang ◽  
Qingchao Meng ◽  
Zhiyan Hu ◽  
...  
Keyword(s):  
Heat Flux ◽  
Power Distribution ◽  
Crystalline Silicon ◽  
Melting Process ◽  
Radiant Heat ◽  
Radiant Heat Transfer ◽  
Single Crystalline ◽  
Seed Crystals ◽  
Partition Block ◽  
Solid Liquid Interface

The preservation of seed crystals is important for the casting of quasi-single crystalline (QSC) silicon ingots. We carried out transient global simulations of the feedstock melting process in an industrial-sized directional solidification (DS) furnace to investigate key factors influencing seed preservation. The power distribution between the top and side heaters is adjusted in the conventional furnace for multicrystalline silicon ingots and in the evolved furnace with a partition block for QSC silicon ingots. The evolution of the solid-liquid interface for melting and the temperature distribution in the furnace core area are analyzed. The power distribution can influence the temperature gradient in the silicon domain significantly. However, its effect on seed preservation is limited in both furnaces. Seed crystals can be preserved in the evolved furnace, as the partition block reduces the radiant heat flux from the insulation walls to the heat exchange block and prevents the heat flowing upwards under the crucible. Therefore, the key to seed preservation is to control radiant heat transfer in the DS furnace and guarantee downward heat flux under the crucible.

Radiation Energy Density and Radiation Heat Flux in Small Rectangular Cavities

1972 ◽  
Vol 94 (3) ◽  
pp. 289-294 ◽  
Author(s):  
R. P. Caren
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Energy Density ◽  
Classical Theory ◽  
Radiant Energy ◽  
Radiation Energy ◽  
Radiant Heat ◽  
Radiant Heat Transfer ◽  
Radiation Heat ◽  
Radiation Energy Density

The present paper investigates the impact of one or more small cavity dimensions on the radiation energy density and radiation heat flux in rectangular metallic cavities. The emphasis of the present analysis is the exact treatment of the modal structure of the electromagnetic field in a small cavity in determining the properties of the thermal radiation field in the cavity. The excitation spectrum of the modes is assumed to be given by the Planck distribution function. The Poynting theorem is invoked in order to determine the radiative heat flux absorbed by the walls from the radiation in the cavity. Variation of the dimensions of the rectangular cavity allows the effects of cavity size and shape on the radiant energy density and radiant heat transfer to be assessed, particularly in several interesting limiting cases. It is found that significant deviations from the classical theory occur whenever any of the cavity dimensions satisfy the inequality lT ≤ 1 cm-deg K. It is further found that, when two or more of the cavity dimensions satisfy the above inequality, the radiant energy density and radiant heat transfer are significantly reduced in comparison to the results of classical theory. However, when only one dimension is limited, as in the case of a closely spaced parallel-surface geometry, the radiant energy density and radiant heat transfer are significantly increased compared to the classical theory.

scholarly journals A Novel Model Concerning the Independence of Emissivity and Absorptivity for Enhancing the Sustainability of Radiant Cooling Technology

2021 ◽  
Author(s):  
Fan Zhang ◽  
Guoqiang Zhang
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Radiant Heat ◽  
Radiant Heat Transfer ◽  
Radiant Heat Flux ◽  
New Model ◽  
The Past ◽  
Radiant Cooling ◽  
Cooling Technology ◽  
Kirchhoff's Law

Abstract Radiant cooling technology is a sustainable technology for improving built environment. The past research only studied the performance (e.g., radiant heat flux) based on Kirchhoff’s law while the accuracy and its reasons were seldom analyzed. In order to study the mechanism deeply, a new model of radiant heat transfer is derived theoretically which considers emissivity and absorptivity independently. This model is validated by the experimental data then applied in a reference case for further analysis. The analyzing methods of sensitivity and relative deviation are performed to investigate the reasons for the errors. The results of sensitivity analysis show that it is about 20% − 40% more sensitive for the emissivity to the heat flux than the absorptivity. Furthermore, the deviation of the heat flux can reach up to 20% when the absorptivity is in the range from 0.4 to 0.9. This deviation is close to the estimated error range of 21.8% in the past studies. Therefore, the discussion based on the theoretical analysis, shows that the errors in past studies are highly due to the oversimplified preconditions for applying Kirchhoff’s law and they ignored the impact of surface absorption. Additionally, the validation in the previous experiments was highly coincidence, since they neglected the key independent tests of the absorptivity and radiant heat flux. Comprehensively, the new model is valuable to provide a more reliable solution for analyzing the radiant heat transfer and for the future design of an independent test of radiant heat flux.

Recombination Characteristics of Single-Crystalline Silicon Wafers with a Damaged Near-Surface Layer

2013 ◽  
Vol 58 (2) ◽  
pp. 142-150 ◽  
Author(s):  
A.V. Sachenko ◽  
◽  
V.P. Kostylev ◽  
V.G. Litovchenko ◽  
V.G. Popov ◽  
...  
Keyword(s):  
Surface Layer ◽  
Crystalline Silicon ◽  
Silicon Wafers ◽  
Single Crystalline Silicon ◽  
Near Surface ◽  
Single Crystalline

The Lattice Boltzmann Investigation for the Melting Process of Phase Change Material in an Inclined Cavity

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Zhonghao Rao ◽  
Yutao Huo ◽  
Yimin Li
Keyword(s):  
Heat Flux ◽  
Phase Change ◽  
Lattice Boltzmann ◽  
Melting Process ◽  
Clockwise Rotation ◽  
Linear Distribution ◽  
Left Wall ◽  
Inclined Cavity ◽  
Solid Liquid ◽  
Change Material

The solid–liquid phase change process is of importance in the usage of phase change material (PCM). In this paper, the phase change lattice Boltzmann (LB) model has been used to investigate the solid–liquid phase change in an inclined cavity. Three heat flux distributions applied to the left wall are investigated: uniform distribution, linear distribution, and parabolic symmetry distribution. The results show that for all the heat flux distributions, the slight clockwise rotation of the cavity can accelerate the melting process. Furthermore, when more heat is transferred to the cavity through the middle part (parabolic symmetry distribution) or bottom part (linear distribution) of left wall, clockwise rotation of cavity leads to larger temperature of PCM.

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