【作者】 范有明；

【导师】 时章明；

【作者基本信息】 中南大学 ， 热能工程， 2007， 硕士

【摘要】 热处理是机械零件和模具制造的最后一道工序,也是最重要工序之一。推杆式可控气氛热处理炉是最常见的一种连续式热处理炉,研究表明:推杆炉内零件渗碳不均匀的主要原因是炉内温度的不均匀及炉气流动不合理,炉温不均匀也与气流分布有关。因此深入了解推杆炉内的气体流场特性,对于改善炉温和流场均匀性、提高渗碳产品质量是十分必要的,对于开发新炉型和指导炉子运行也有着重要的理论和实践意义。论文介绍了推杆式热处理炉的结构组成和特点,说明了渗碳热处理对炉内流场的要求。在此基础上建立了炉内三维流场稳态数值计算模型,以计算流体力学软件FLUENT为求解工具对炉内流场进行计算。湍流模型采用标准κ-ε模型,选择控制容积法对方程组进行离散,压力与速度耦合采用SIMPLE算法。得到了空炉内状态下炉内压力、流场的分布情况。在此基础上,研究了风扇转速和竖置导流板的布置对炉内气流分布、流速和流场均匀性影响。计算了炉子前后排气比对渗碳区和扩散区气流交换的影响。本文的创新点在于把数值模拟技术首次引入用于化学热处理的连续式热处理炉,为炉子设计、改造以及优化运行都有理论和实践指导意义。论文工作也拓展了热处理的研究范围。更多还原

【Abstract】 Heat treatment is final as well as one of the most important procedures in accessory and mould produce. Push-type furnace is widely used as a kind of continuous heat treatment furnace. Previous research indicated that carburizing ununiformity is mostly likely caused by the ununiformity of temperature distribution and immoderate gas flow, what’s more, temperature ununiformity relates on gas flow distribution. Therefore, it’s necessary to understand the gas flow characteristic in furnace, so that the temperature and flow field are improved which lead to improvement of carburizing product. It’s also useful in developing new furnace and optimizing the run of existing furnace.The structure and characteristic of push-type furnace is introduced, the flow manner and speciality in furnace is analyzed. A 3-D cold-state steady numerical simulation model for the turbulence flow in furnace is established. The simulation is base onκ-εturbulence model, control volume method is chosed for equation dispersation, SIMPLE arithmetic is used for the coupling of pressure and speed. The pressure and flow distribution in furnace is gained.Cases under different fan speed and the disposal of erect baffle were computed. The flow field distribution、gas speed、flow uniformity effected by the two factors were analysed. The effect of mass outflow proratation between ahead and end venthole to gas exchange between carburizing and diffusion region was researched.The innovation of the paper is that, CFD was employed for the research of the flow field in continuous heat treatment furnace. It’s meaningful in directing design new type furnace and help to improve the the run of existing furnace.What’s more, the paper research expand the research of heat treatment.更多还原