碳热还原合成碳化硅过程的数值模拟

摘要

In order to reveal the mechanism of energy and material diffusion in the process of silicon carbide synthesis so as to lay the theoretical foundation to improve the yield and quality of silicon carbide,the numerical simulation method was used to simulate the temperature field,pressure field and gas flow in the process of silicon carbide synthesis.The results showed that with the increase of the synthesis time,the heat in the furnace was radiated outward and the gas in the synthesis furnace exhibited three-dimensional multi-directional flow characteristic.When the reaction progressed to 24 h,the gas flow rate reached the maximum.At this moment,due to the poor ventilation at the bottom of the furnace,the pressure at this point was higher than the remaining position and the maximum was 1.525× 101 kPa.At this time,a small amount of wood chips can be added to increase the permeability of the furnace to improve the pressure to avoid the spouting of furnace by the over high pressure.The simulation results have been verified by the production practice.%为揭示碳化硅合成过程中能量及物质扩散机理,从而为碳化硅的提质增产奠定理论基础,采用数值模拟的方法对碳化硅合成过程中的温度场、压力场、气体流动规律进行模拟研究.结果表明,随着合成时间的延长,炉内热量呈辐射状向外扩散,合成炉内气体呈现三维多向流动特性,反应进行到24 h时CO气体流量达到最大,而此时由于炉底透气性差的原因,致使炉底部压力高于其余位置,最大可达1.525× 101 kPa,此时可加入少量木屑以增加炉底透气性来改善因压力过高所造成的喷炉事故.模拟结果得到了生产实践验证.