【作者】 黄哲庆；

【导师】 刘春江；

【作者基本信息】 天津大学 ， 化学工程， 2013， 博士

【摘要】 本文旨在开发低能耗的新型多晶硅CVD反应器，并采用计算流体力学的方法研究反应器的动量、热量、质量传递及化学反应过程，以指导反应器的优化与设计，进一步降低反应器的还原电耗。本文第二部分首先介绍了现有多晶硅CVD反应器的结构及操作流程，分析了现有反应器的硅棒的排布方式，讨论了现有反应器的进气和出气方式，列举了现有一些反应器的底盘冷却结构。本文第三部分采用多表面辐射传热模型（S2S）研究了多晶硅CVD反应器的辐射传热过程，计算结果表明反应器从12对棒放大到18对棒和27对棒，反应器的辐射能耗分别降低7.8%和20.8%；将多晶硅的沉积速率从5μm min-1提高到20μm min-1，反应器的辐射能耗可降低75%；将反应器壁面的温度从373K提高到773K，反应器的辐射能耗可降低9.6%；将反应器内壁面的发射率从0.2降低到0.1，反应器的辐射能耗可降低的61.6%；另外通过比较了两种不同的硅棒排布的反应器辐射能耗，结果发现圆周排布反应器的硅棒与反应器壁面之间的辐射功率更低，硅棒与硅棒之间的辐射功率更高，这表明了在圆周排布反应器的硅棒排布更加密。本文第四部分在传统多晶硅CVD反应器基础上提出了一种新型反应器，并根据工业尾气组分推导反应器内的反应方程式，耦合这一反应模型，建立了描述反应器内动量、热量、质量同时传递及化学反应的数学模型，应用该模型分析了两反应器的性能。模拟结果表明：首先新型反应器内混合气的流场更加均匀，基本上为“平推式流动”，解决了传统反应器原料气走短路问题；其次新型反应器解决了传统反应器顶部区域温度过高的问题，避免了硅粉的生成，长期保持反应器内壁面的光洁度，从而降低了反应器的辐射能耗；第三，新型反应器内三氯氢硅在径向和轴向方向上都存在着较大的浓度差，这种浓度差可能造成多晶硅棒的直径不同，但是与上述两点相比，这种浓度分布不均匀对多晶硅棒直径的影响是可以接受的；最后与传统反应器结构的还原电耗相比，新型反应器的还原电耗至少可降低10%以上。本文第五部分提出了一种新型多晶硅CVD反应器的底盘冷却结构，并采用计算流体力学的方法模拟了新型结构的流动过程，模拟结果发现通过减小电极套筒的大小，减小电极套筒与底盘下底板的间距，改变中间隔板与底盘下底板的间距，都可以提高电极套筒流量的均匀度。更多还原

【Abstract】 The purpose of the paper is to develop a novel energy saving polysilicon CVDreactor. In order to guide the optimization and design of the reactor and reduce theenergy consumption, the flow behavior, the heat and mass transfer, the speciestransport and chemical vapor deposition reaction in the polysilicon CVD reactor havebeen modeled by using the computational fluid dynamic method.In the second part of this dissertation, the structure of the polysilicon CVDreactor and the operation process have been introduced, the arrangement of thepolysilicon rods has been analyzed; the inlet and outlet of the gases have beendiscussed and several cooling structures of the chassis have been presented.In the third part, the radiation heat transfer of the reactor has been simulated byusing the S2S model. The simulation results demonstrate that enlarging the reactorcapacity from12rods to18rods and27rods can reduce the energy loss by7.8%and20.8%respectively; if the polysilicon growth rate is increased from5to20μm min-1,the radiation energy consumption can be reduced by75%; increasing the inner shieldtemperature from373to773K, the energy saving is9.6%; changing the emissivity ofthe inner shield from0.2to0.1decreases the energy loss by38.3%. Furthermore, theradiation energy consumption has been compared between the circular arrangementreactor and the hexagonal arrangement reactor. The results show that the radiationpower in the circular arrangement reactor between the polysilicon rods and the reactorwall is lower than that in hexagonal arrangement reactor and the power in the circulararrangement reactor between the polysilicon rods are more than that in hexagonalarrangement reactor, the results demonstrate that the polysilicon rods arrangement inthe circular arrangement reactor is more encryption than that in hexagonalarrangement reactor.Based on the traditional polysilicon CVD reactor, a novel reactor with lowerenergy consumption is developed and a three dimensional theoretical model todescribe the transport phenomena in the reactor is proposed. An overall chemicalreaction formula is developed according to the measured composition of the exhaustgas in a polysilicon factory. By comparing the simulated results with industrial datafor traditional polysilicon CVD reactor, the proposed model has been verified. Thevelocity profile, temperature field, concentration distribution and the energyconsumption of the traditional reactor and novel reactor have been analyzed using the theoretical model. The simulation results demonstrate that the flow pattern of the gasmixture in the novel reactor is nearly plug flow, which is fundamentally different fromthat of traditional reactor, and the temperature field can be controlled by changing theoperating parameters in the novel reactor. Because the temperature of the gas phase inthe novel reactor can be controlled, the chance of silicon powder generation can beavoided, and the cleanness of the inner wall of the reactor can be kept at95%above.Simulation results shows that the energy consumption of the novel reactor can begreatly reduced due to lower radiation on the cleaner inner wall.Finally, the paper presents a novel cooling structure of the chassis in polysiliconCVD reactor, the flow behavior in the novel chassis has been modeled by using thecomputational fluid dynamic. The simulation result demonstrate that by reducing thesize of the electrode sleeve and the distance between the electrode sleeve and thebottom plane of the chassis can increase the uniform of the mass flow between theelectrode sleeves; changing the distance between the middle plane and the bottomplane in the chassis can also increase the uniform of the mass flow between theelectrode sleeves.更多还原