Local and Global Simulations of Bridgman and Liquid-Encapsulated Czochralski Crystal Growth

1998 ◽  
Vol 120 (4) ◽  
pp. 865-873 ◽  
Author(s):  
H. Zhang ◽  
L. L. Zheng ◽  
V. Prasad ◽  
D. J. Larson
Keyword(s):  
Crystal Growth ◽  
Interface Shape ◽  
Original Formulation ◽  
Gaas Crystal ◽  
Global Modeling ◽  
Convective Flows ◽  
Gas Phases ◽  
Bismuth Crystal ◽  
Transient Simulations ◽  
First Time

A curvilinear finite volume-based numerical methodology has been developed that can be effectively used for simulation of the Bridgman and Czochralski (Cz) crystal growth processes. New features of grid generation have been devised and added to the original formulation (Zhang et al., 1995, 1996) to make it suitable for global modeling. The numerical model can account for convection in both the melt and the gas phases, convection/radiation in the furnace, and conduction in all solid components. Results for Bridgman growth show that the flow pattern and interface shape strongly depend on thermal conductivities of the crystal, melt, and ampoule materials. Transient simulations have been performed for the growth of Bismuth crystal in a Bridgman-Stockbarger system and the growth of GaAs crystal using liquid-encapsulated Czochralski (LEC) technique. This is the first time that a global high-pressure LEC model is able to account for convective flows and heat transfer and predict the interface shape and its dynamics.

scholarly journals Axial Compressor Mean-Line Analysis: Choking Modelling and Fully-Coupled Integration in Engine Performance Simulations

2021 ◽  
Vol 6 (1) ◽  
pp. 4
Author(s):  
Ioannis Kolias ◽  
Alexios Alexiou ◽  
Nikolaos Aretakis ◽  
Konstantinos Mathioudakis
Keyword(s):  
Axial Compressor ◽  
Engine Performance ◽  
Engine Model ◽  
Multi Stage ◽  
Transient Simulations ◽  
Full Knowledge ◽  
Compressor Performance ◽  
First Time ◽  
Performance Calculation ◽  
Fully Coupled

A mean-line compressor performance calculation method is presented that covers the entire operating range, including the choked region of the map. It can be directly integrated into overall engine performance models, as it is developed in the same simulation environment. The code materializing the model can inherit the same interfaces, fluid models, and solvers, as the engine cycle model, allowing consistent, transparent, and robust simulations. In order to deal with convergence problems when the compressor operates close to or within the choked operation region, an approach to model choking conditions at blade row and overall compressor level is proposed. The choked portion of the compressor characteristics map is thus numerically established, allowing full knowledge and handling of inter-stage flow conditions. Such choking modelling capabilities are illustrated, for the first time in the open literature, for the case of multi-stage compressors. Integration capabilities of the 1D code within an overall engine model are demonstrated through steady state and transient simulations of a contemporary turbofan layout. Advantages offered by this approach are discussed, while comparison of using alternative approaches for representing compressor performance in overall engine models is discussed.

Large-sized crystal growth and piezoelectric properties of the single crystals of LiNa5Mo9O30

CrystEngComm ◽  
2021 ◽  
Vol 23 (9) ◽  
pp. 1912-1917
Author(s):  
Xiaoli Du ◽  
Fuan Liu ◽  
Zeliang Gao ◽  
Xiaojie Guo ◽  
Xiangmei Wang ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Crystal Growth ◽  
Single Crystals ◽  
Piezoelectric Properties ◽  
First Time ◽  
Octahedral Distortion

Single crystals of LiNa5Mo9O30 with seeds in the a-, b- and c-directions were successfully grown using the TSSG method. Full sets of dielectric, elastic and piezoelectric matrices of the crystal were determined first time. The octahedral distortion and dipole moment are calculated to explain the piezoelectric properties.

Boron- and stoichiometry-related defect engineering during B2O3-free GaAs crystal growth

2009 ◽  
Vol 6 (12) ◽  
pp. 2778-2784 ◽  
Author(s):  
F.-M. Kiessling ◽  
M. Albrecht ◽  
K. Irmscher ◽  
M. Roßberg ◽  
P. Rudolph ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Gaas Crystal ◽  
Defect Engineering ◽  
Related Defect

A numerical and experimental study of natural convection and interface shape in crystal growth

1997 ◽  
Vol 173 (3-4) ◽  
pp. 492-502 ◽  
Author(s):  
G.H. Yeoh ◽  
G. de Vahl Davis ◽  
E. Leonardi ◽  
H.C. de Groh ◽  
M. Yao
Keyword(s):  
Experimental Study ◽  
Crystal Growth ◽  
Natural Convection ◽  
Interface Shape

Large modification of crystal–melt interface shape during Si crystal growth by using electromagnetic Czochralski method (EMCZ)

2006 ◽  
Vol 292 (2) ◽  
pp. 252-256 ◽  
Author(s):  
Masahito Watanabe ◽  
Daniel Vizman ◽  
Jochen Friedrich ◽  
Georg Müller
Keyword(s):  
Crystal Growth ◽  
Czochralski Method ◽  
Interface Shape

Optimization of Bulk Hgcdte Growth in a Directional Solidification Furnace by Numerical Simulation

1995 ◽  
Vol 398 ◽  
Author(s):  
A.V. Bune ◽  
D.C. Gillies ◽  
S.L. Lehoczky
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Finite Element ◽  
Crystal Growth ◽  
Numerical Model ◽  
Directional Solidification ◽  
Growth Conditions ◽  
Finite Element Code ◽  
Interface Shape ◽  
Solidification Furnace

ABSTRACTA numerical model of heat transfer by combined conduction, radiation and convection was developed using the FIDAP finite element code for NASA's Advanced Automated Directional Solidification Furnace (AADSF). The prediction of the temperature gradient in an ampoule with HgCdTe is a necessity for the evaluation of whether or not the temperature set points for furnace heaters and the details of cartridge design ensure optimal crystal growth conditions for this material and size of crystal. A prediction of crystal/melt interface shape and the flow patterns in HgCdTe are available using a separate complementary model.

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