| With the development of electronic technology,more and more semiconductor materials have attracted the attention of researchers.So,the manufacturing of semiconductor materials has become a research focus,especially single crystals which has high quality.There are many factors which affect the quality of single crystal,including thermal field conditions,heating process and time control,it's very important for the growth of single crystal to match the suitable thermal field conditions.Nowadays,many scholars are devoted to analyze and study the thermal field of single crystal furnace.It is necessary to study the thermal system whether the growth method of single crystal is CZ method or Zone melting.There are many problems in temperature control of single crystal furnace.The main problem is that it is difficult to achieve a large temperature gradient which can satisfy crystal growth.So this is the main research purpose: a double coil induction heating device is designed to control the temperature field effectively by adjusting the induction heating current,frequency,coil height ratio and other parameters.In this paper,single crystal furnace is the research background,combined with the theoretical basis of electromagnetic induction heating,by using finite element software ANSYS and ELTA to simulate and analyze the induction heating process of graphite sleeve.ELTA is a unique program with a wide range of applications,including induction heating process and equipment design,induction heating coil and power supply matching.The simulation of electromagnetic field and thermal field in induction heating process is fast and reasonable.Firstly,ELTA software was used to calculate the voltage values of different graphite sleeve diameters and coil turns.The outer diameter of the graphite sleeve and the number of turns about coils are determined by comparing with the specific parameters of the power supply cabinet in the laboratory.Then,ANSYS electromagnetic-thermal coupling module is used to simulate the heating process of graphite sleeve.The heating device is modeled-attached to attribute-grid-loaded boundary conditions and load-solved,and the temperature field variation rules were simulated and analyzed under different induction heating currents,frequencies and coil height ratios.The suitable temperature gradient of graphite sleeve can be obtained by adjusting the parameters of induction coil.Finally,the temperature measurement experiment of induction heating is carried out.The temperature measuring instrument was used to monitor and record the temperature distribution under different currents and frequencies in real time,and the experimental results are compared with the simulation results,proving the accuracy of the simulation results.Through simulation calculation and analysis,the current intensity,frequency and coil height ratio have significant influence on the distribution of temperature field,and the design of double coil can easily achieve a large longitudinal temperature gradient.According to the simulation results,the double-coil induction heating device is designed and the induction heating experiment is carried out.The conclusions are as follows: When the frequency of double coil are 400 Hz and 1000 Hz,the current is 73 A?28A,the heating time of 300 s,temperature measuring instrument measured temperature is 243.8 ?,the simulation of the temperature is 282.5 ?.Obviously simulation value is higher than the experimental value.The relative error is in allowable range of the experiment and the value is 13.6%,which can prove the accuracy of the numerical simulation results. |
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