scholarly journals Influence of Different Heater Structures on the Temperature Field of AlN Crystal Growth by Resistance Heating

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7441
Author(s):  
Ruixian Yu ◽  
Chengmin Chen ◽  
Guodong Wang ◽  
Guangxia Liu ◽  
Shouzhi Wang ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Temperature Gradient ◽  
Heat Transfer Process ◽  
Resistance Furnace ◽  
Zone Structure ◽  
Axial Temperature Gradient ◽  
Axial Temperature ◽  
Adjustable Range ◽  
Hot Zone ◽  
Bottom Heater

Based on the actual hot zone structure of an AlN crystal growth resistance furnace, the global numerical simulation on the heat transfer process in the AlN crystal growth was performed. The influence of different heater structures on the growth of AlN crystals was investigated. It was found that the top heater can effectively reduce the axial temperature gradient, and the side heater 2 has a similar effect on the axial gradient, but the effect feedback is slightly weaker. The axial temperature gradient tends to increase when the bottom heater is added to the furnace, and the adjustable range of the axial temperature gradient of the side 1 heater + bottom heater mode is the largest. Our work will provide important reference values for AlN crystal growth by the resistance method.

Controlling the axial temperature gradient in inductively heated Czochralski systems

2003 ◽  
Vol 38 (1) ◽  
pp. 42-46 ◽  
Author(s):  
S. Ganschow ◽  
P. Reiche ◽  
M. Ziem ◽  
R. Uecker
Keyword(s):  
Temperature Gradient ◽  
Axial Temperature Gradient ◽  
Axial Temperature

Amplification of energy flux of nonlinear acoustic waves in a gas-filled tube under an axial temperature gradient

2002 ◽  
Vol 456 ◽  
pp. 377-409 ◽  
Author(s):  
N. SUGIMOTO ◽  
K. TSUJIMOTO
Keyword(s):  
Boundary Layer ◽  
Temperature Gradient ◽  
Energy Flux ◽  
Acoustic Waves ◽  
Wave Equations ◽  
Main Flow ◽  
Nonlinear Wave Equations ◽  
Axial Temperature Gradient ◽  
Axial Temperature ◽  
Nonlinear Acoustic

This paper considers nonlinear acoustic waves propagating unidirectionally in a gas-filled tube under an axial temperature gradient, and examines whether the energy flux of the waves can be amplified by thermoacoustic effects. An array of Helmholtz resonators is connected to the tube axially to avoid shock formation which would otherwise give rise to nonlinear damping of the energy flux. The amplification is expected to be caused by action of the boundary layer doing reverse work, in the presence of the temperature gradient, on the acoustic main flow outside the boundary layer. By the linear theory, the velocity at the edge of the boundary layer is given in terms of the fractional derivatives of the axial velocity of the gas in the acoustic main flow. It is clearly seen how the temperature gradient controls the velocity at the edge. The velocity is almost in phase with the heat flux into the boundary layer from the wall. With effects of both the boundary layer and the array of resonators taken into account, nonlinear wave equations for unidirectional propagation in the tube are derived. Assuming a constant temperature gradient along the tube, the evolution of compression pulses is solved numerically by imposing the initial profiles of both an acoustic solitary wave and of a square pulse. It is revealed that when a positive gradient is imposed, the excess pressure decreases while the particle velocity increases and that the total energy flux can indeed be amplified if the gradient is suitable.

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