碳纳米管化学气相沉积炉的优化设计与仿真

发布时间：2018-03-02 06:35

本文关键词： 碳纳米管化学气相沉积炉温度场流场数值模拟　出处：《南昌大学》2015年硕士论文　论文类型：学位论文

【摘要】：碳纳米管由于其独特的结构而具有优越的机械、电学和热学等性能,在复合材料、催化剂载体、锂离子电池、场发射材料和隐形材料等领域表现出很好的应用前景。目前生产碳纳米管的主要方式为化学气相沉积法,但该法生产的碳纳米管存在石墨化程度不高,曲率大,相互缠绕不易分散等缺陷。所以基于化学气相沉积法,开发研究制备优质碳纳米管的工艺和装备是当前研究的热点。本课题组基于化学气相沉积法,研制设计生产优质碳纳米管的化学气相沉积炉。深入了解生产碳纳米管时沉积炉内的温度场和流场分布情况,对于指导碳纳米管的合成工艺研究具有重要意义。分析旋风分离器中的流场分布情况和其分离效果,对于装置结构的设计和改进具有重要的实践意义。本文首先对沉积炉的结构进行了设计,然后根据化学气相沉积炉的几何尺寸,建立了沉积炉传热的二维和三维计算模型,基于FLUENT平台,对化学气相沉积炉合成碳纳米管的过程进行了非稳态数值模拟,得到了炉膛内的温度场及流场分布情况,并与实验结果进行了对比分析。最后,以旋风分离器为研究对象,建立了分离器的三维计算模型,运用FLUENT软件,对分离器的分离过程进行了数值模拟,得到了分离器中的流场分布情况和碳纳米管的运动轨迹。模拟结果显示,沉积炉内二维和三维结果基本一致。气流主要影响炉膛一区和二区的中心区域,但对三区和四区的影响较小。炉膛内的温度场并不是均匀分布的,沿轴向方向上温度呈上高下低的趋势(中心区域除外);沿径向上炉膛内温度在一区有较大的变化,而在二三四区基本维持相对稳定的温度。发热体处的模拟温度和实测温度之间的最大误差率在误差允许范围内,说明模型比较可靠,模拟结果有一定的参考价值。分离器中气体相的流动主要是双层旋流,向下旋转运动的外旋流和向上旋转的内旋流,两者旋向相同。颗粒物的粒径和入口位置对颗粒相在旋风分离器中的运动轨迹影响很大。旋风分离器的结构和流体参数对分离器的分离效率影响较大。
[Abstract]:Carbon nanotubes have superior mechanical because of its unique structure, electrical and thermal properties in composite materials, catalyst carrier, lithium ion battery, field emission materials and stealth materials show good prospects. The main way for the production of carbon nanotubes by chemical vapor deposition method, but the method of production the graphitization degree of carbon nanotubes are not high, large curvature, mutual winding can not be dispersed and other defects. So based on the chemical vapor deposition method, the research and development of preparation technology and equipment of high quality carbon nanotubes is the focus of current research. This topic is based on the chemical vapor deposition, chemical gas development and production of high quality carbon nanotubes the design of phase deposition furnace. An in-depth understanding of production of carbon nanotubes deposited in the furnace temperature field and flow field distribution, which is very important to study the synthesis process of direct carbon nanotubes. Analysis of cyclone separator The flow field distribution and effect of its isolation, the design and the device structure has important practical significance. Firstly the structure of deposition furnace is designed, and then according to the geometry of a chemical vapor deposition furnace, a two-dimensional and three-dimensional deposition furnace heat transfer calculation model based on the FLUENT platform, the simulation steady state numerical process of chemical vapor deposition furnace synthesis of carbon nanotubes, the temperature field and flow field distribution inside the furnace, and compared with the experimental results. Finally, the research object in the cyclone, established a three-dimensional calculation model of the separator, the use of FLUENT software, the numerical simulation of the separation process the separator, the trajectory of the flow field distribution and carbon nanotubes in the separator. The simulation results show that the deposition furnace 2D and 3D flow of main results are basically the same. To influence regional center for the region and the two region, but has little effect on the three and four areas. The temperature field in the furnace is not evenly distributed along the axial direction, the temperature in the low end of the trend (central region except); along the radial direction on the furnace temperature in the region have great changes but, in the 234 District remained relatively stable temperature. The maximum error between the simulation temperature and heating rate of the measured temperature in the range of allowable error, the model is reliable, the simulation results have a certain reference value. The main flow in gas phase separator if double vortex, rotating downward swirl and to on the rotating flow, the same rotation direction. The particle size and the entrance position on the particle trajectory in the cyclone separator is greatly affected. The efficiency of the separator structure and fluid parameters of cyclone separator It has great influence.

【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ127.11;TB383.1

【共引文献】