双排料步进梁式加热炉壁面发射率对钢坯温度均匀性影响

Effect of wall emissivity on slabs temperature uniformity in double-row walking-beam reheating furnace

加热炉能耗占钢铁企业总能耗的15%~20%,占轧钢过程能耗的70%,具有很大的研究价值。基于计算流体力学方法建立数学模型,研究双排料步进式加热炉中钢坯的加热过程,通过对比模拟结果与黑匣子数据,验证模型的可行性。根据炉内钢坯沿炉长方向各热通量的变化,研究了炉壁各区域和炉膛发射率对钢坯加热过程的影响。结果表明,提高炉壁发射率对钢坯平均温度影响较小,但对钢坯温差有显著影响;而壁面发射率由0.75提高到0.95时,钢坯的最佳驻炉时间可减少5%~12%;相比于一加段和均热段,烟气预热段、预热段和第2加热段壁面发射率的增加对钢坯加热过程影响更大。综合考虑经济成本和生产效率,现场可以通过在烟气预热段、预热段、第2加热段炉壁应用发射率为0.85的涂层,以增强炉内辐射换热,提升钢坯加热质量。研究结果为加热炉实际生产提供了理论依据。

The reheating furnace accounts for 15%-20%of the total energy consumption for enterprise and 70%of the energy consumption of slab rolling process,which is of great value to research.A mathematical model based on the computational fluid dynamics method was developed to study the heating process of slabs in double-row walking-beam reheating furnace.The feasibility of the model was validated by comparing the simulation results with the black box data.The effect for emissivity of furnace wall areas and furnace chamber on the heating process of slabs were investigated according to the variation of each heat flux in the slabs along the furnace length.The results show that increasing the furnace wall emissivity has small effect on average slabs temperature but significant effect on the slabs temperature difference.While the wall emissivity is increased from 0.75 to 0.95,the optimum residence time of slabs can be reduced by 5%-12%.The increase of wall emissivity in the flue gas preheating zone,preheating zone and second heating zone has greater impact on the slabs heating process than the first heating zone and the soaking zone.Taking into account economic costs and production efficiency,the quality of slabs heating can be improved in industrial processes by applying emissivity of 0.85 coating to the walls of flue gas preheating zone,preheating zone and second heating zone to enhance radiative heat exchange in the furnace.The study results provide theoretical basis for the practical production of reheating furnaces.