总括热吸收率的补偿辨识

Compensation Identification for Total Heat Exchange Factor

总括热吸收率(φCF)是连续加热炉L2级控制系统的重要参数.它既受炉子结构参数的影响,也受操作参数的影响,研究其补偿辨识尤为重要.提出基于炉温的一段式三元模型.取三元模型的任意一个模型段,以炉温和钢坯表面温度为输入条件,建立热电偶模型,并耦合求解热电偶及炉墙能量平衡方程,最终得到钢坯表面热流,进而对φCF进行反向分析.分别考察了温度、钢坯规格及钢坯表面温度变化对φCF的影响.结果表明,当炉温恒定时,φCF随钢温的升高而减小,当钢温接近炉温时,φCF变化率的绝对值迅速增大;而当钢温恒定时,φCF随炉温的升高而增大.另外,φCF随钢坯长度和宽度的增加而增大,随钢坯表面黑度的增加而增加.

The total heat exchange factor（φCF） is the important parameter for the L2 control system of reheating furnace.φCFis influenced by the furnace structure parameters and operating parameters.So the compensation identification for φCF is very important.The solo ternary model based on the furnace temperature was developed.Taking any model section of a ternary model,the temperatures of the furnace and of the slab surface were used as input conditions,the thermocouple model was developed and the energy equations of the thermocouple and furnace wall were established.Finally,the heat flux of slab surface was solved.So the identification for φCF was researched.The influences for φCFby the temperature,size of slab and the temperature change of the slab were researched.The results demonstrated that the value of φCFdecreased with the increase of the slab temperature,when the furnace temperature was constant.When the slab temperature was closed to the furnace temperature,the absolute value of the gradient for the variation of φCF increased rapidly.While the slab temperature was constant,the value of φCF increased with the increase of furnace temperature.Moreover,the φCF increased with the increase of the length and width of the slab,and also increased with the increase of the emissivity for the slab.