【作者】 赵迪；

【导师】 欧俭平；

【作者基本信息】 中南大学 ， 热能工程， 2009， 硕士

【摘要】 辊底式均热炉是紧凑式带钢生产工艺中关键热工设备,开展降低该工艺高碳钢坯氧化烧损的研究,对提高热轧板卷表面质量、降低吨钢成本有重要理论和实际意义。本文对国内外氧化烧损的研究和数值模拟技术在轧钢加热炉中的应用现状进行综述,根据CSP均热工艺对实验炉内氧化烧损量的定量计算,研究了合理组织辊底式均热炉内燃烧和高温烟气流动的工况调节方法以优化均热过程降低钢坯氧化烧损。主要研究内容包括:(1)通过介绍纯铁在空气中的氧化过程引入钢的氧化机理,对影响钢坯氧化烧损的主要因素、钢坯氧化烧损量经验计算模型进行综述,并分析了制定辊底式均热炉高碳钢坯均热工艺的策略。(2)对描述加热炉内流动、传热及燃烧过程的数学理论和钢坯氧化模型进行系统阐述,根据国内外研究成果和CSP均热工艺特点,确定了辊底式均热炉钢坯氧化烧损数学模型,并分别利用实验均热炉实验数据和文献数据对所建模型钢坯温度和钢坯烧损量计算准确性进行了验证。(3)在现有加热炉内钢坯氧化机理研究成果的基础上,基于FLUENT软件和氧化烧损子程序,研究加热速率、均热温度和加热气氛等热工因素对65Mn钢均热过程氧化烧损的影响,结果表明,提高加热速度可降低钢坯氧化烧损,增大均热温度和空气消耗系数则使钢坯氧化加剧。(4)根据CSP均热工艺特点,以实验均热炉为研究对象,研究空气消耗系数、中心风和二次助燃风量之比以及空气预热温度对实验炉内流体流动、燃烧及炉气与钢坯间耦合换热的影响,获得了炉内氧化性气体分布、钢坯温度特性等重要信息,为组织均热炉内高温烟气流动和燃烧提供了参考。更多还原

【Abstract】 The roller hearth reheating furnace is the key thermotechical facility of compact strip production (CSP). The study of iron scale mechanism on high-carbon billet in the soaking process of this technology was carried out. It was propitious to ameliorate the quality of hot rolled steel sheet and reduce the cost.In this thesis, the latest research results on oxidation of steel and the application of numerical simulation on reheating furnace were analyzed. Based on the computation of loss of iron scale in an experimental furnace according to the soaking process of CSP line, the methods of organizing combustion and high temperature gas fluid flow in the roller hearth reheating furnace were studied to optimize the soaking process and reduce loss of iron scale. The principal contents of this thesis are summarized as following:(1) By introducing the oxidation process of pure iron in air, the oxidation mechanism of steel was described. Many important theories about iron scale were summarized, such as, the principal factors of influencing oxidation of billet in reheating furnaces, the empirical computational models of loss of iron scale, etc. What’s more, the soaking strategies of high-carbon steel in the roller hearth reheating furnace were analyzed as well.(2) The mathematical theories about modeling fluid flow, heat transfer and combustion in reheating furnaces and the computational model of loss of iron scale were summarized. And the mathematical model of computing loss of iron scale in the roller hearth reheating furnace was established according to both the latest domestic and overseas research results and the characteristics of the soaking process of CSP line. The mathematical model was verified by experimental results of gas temperature and the literature data of loss of iron scale.(3) Based on the latest research results of iron scale mechanism in reheating furnaces, Computational Fluid Dynamics (CFD) software FLUENT 6.2 integrated with computational program of loss of iron scale was used to research the effects of rate of reheating, soaking temperature and soaking atmosphere on the soaking process of 65Mn steel. The numerical simulation results show that the loss of iron scale reduces while increasing the rate of reheating, and it increases with increasing the soaking temperature as well as increasing air consumption ratio.(4) According to the technological characteristics of the soaking process in CSP line, the effects of air consumption ratio, the ratio of the capacity of core air to the capacity of secondary air and air preheating temperature on fluid flow, combustion and the heat transfer between gas and billet were studied experimentally. Some key information, such as, the distribution of oxidizing gas on surface of billet, the temperature of billet, etc, were obtained. Those are important reference data for organizing high temperature gas fluid flow and combustion in the roller hearth reheating furnace.更多还原