Temperature Field Design Of Single Crystal Growth Furnace By Plasma Torch Melting

The crystal growth methods commonly used at present include hydrothermal method,pull method,flame melting method,etc.The single crystal preparation methods are based on conventional power supply or hydrogen gas as the heat source,and the temperature and redox conditions are limited.Therefore,the research,production and application of new materials for special high temperature oxide single crystal are limited.The plasma heat source has the advantages of high temperature and controllable redox conditions,which is of great significance to the development,preparation and application of new functional materials.The temperature distribution in the plasma torch crystal growth furnace is closely related to the temperature of plasma heat source,gas flow,flow rate of external air conditioner and structure of furnace body,and the process includes coupling of turbulence flow,convection and radiation heat transfer.Fluent software can be used to simulate various types of fluid flow.It is the most commonly used software for heat conduction,convection,radiation heat transfer and other problems.Based on the growth conditions of rutile single crystal,the temperature field characteristics and variation law of single crystal growth furnace by plasma torch flame melting are analyzed.Firstly,the properties and uses of special high temperature oxide single crystal are introduced.Secondly,the growth method and temperature field design of special high temperature oxide single crystal are introduced.The conclusion is that these methods are solved by special means To solve the problem of the growth of special high temperature oxide crystal,the key technology is to form the temperature distribution,namely the temperature field,which is needed for the growth of the special high temperature oxide crystal.Finally,the temperature field design model of RF plasma torch single crystal growth furnace is established;the physical model of RF plasma torch single crystal growth furnace is simplified,and the data acquisition point is analyzed;the mathematical model adopted includes basic control equation,turbulence model and radiation model;the grid division mode,starting and boundary conditions are described,and the conclusions are as follows:(1)With the increase of plasma temperature,the temperature gradient of axial and longitudinal increases,and the temperature of growth chamber increases as a whole;with the increase of gas velocity,the axial and radial temperature at the growth interface increases,but the radial temperature at the heat source decreases;with the increase of external air conditioner,the wall temperature decreases;when it increases to a certain value,the effect decreases.(2)When the gas velocity,the speed of the external air conditioner and the temperature of the heat source are unchanged,the crystal diameter increases with the decrease of the growth interface position;when the speed of the external air-conditioning,the temperature of the heat source and the position of the growth interface are unchanged,the crystal diameter decreases with the increase of the gas speed;when the gas speed,the external air-conditioning speed and the growth interface are constant,the crystal diameter increases with the increase of the temperature of the heat source.(3)When the connection part of plasma torch and crystal growth furnace is changed from the transition state without transition before to the transition state with chamfering,the crystal diameter increases,but the effect is not obvious;when the chamfering length is increased,the diameter of crystal increases but the effect is not obvious,and the crystal diameter reaches the maximum value when the chamfering length is 15 mm.