连铸保护渣热阻的数值模拟与实验研究

Numerical simulation and experimental study of thermal resistance of continuous casting mold flux

量化保护渣热阻对于提高连铸工艺水平和铸坯质量具有重要意义。本文采用数值模拟和传热实验两种方法对典型连铸结晶器保护渣的热阻进行了研究。首先使用ANSYS数值模拟软件建立铸坯通过渣道向结晶器的导热和辐射耦合传热模型,得到渣道两侧交界面温度分布;随后构建保护渣热阻计算模型,用模拟的传热结果评估固态保护渣和液态保护渣的厚度、导热热阻和辐射热阻;同时构建连铸保护渣稳态传热实验,通过水冷铜探头实验测量保护渣两侧的温度分布,进而得到不同厚度渣道的综合热阻。数值模拟结果表明,当铸坯表面温度从1415℃降为1345℃时,液态保护渣在结晶器上部迅速由1.7 mm减薄为1.04mm,模拟总热阻沿拉坯方向由0.67×10^(-3)m^(2)·K/W增加到1.46×10^(-3)m^(2)·K/W。热阻传热实验结果表明,实验获得的综合热阻较数值模拟偏小,渣道的综合热阻随厚度增加而升高,典型热阻值为(2.28~7.89)×10^(-4)m^(2)·K/W。

Quantification of mould flux thermal resistance is important for improving the level of continuous casting process and billet quality.In this paper,the thermal resistance of typical continuous casting mould flux is studied by two methods:numerical simulation and heat transfer experiment.First of all,use ANSYS numerical simulation software to establish the billet through the slag channel to the mould thermal conductivity and radiation coupling heat transfer model,to obtain the temperature distribution of the interface on both sides of the slag channel;subsequent modeling of the thermal resistance calculation of the mould flux,the results of the simulated heat transfer were used to evaluate the thickness,conduction thermal resistance and radiation thermal resistance of the solid and liquid mould flux;At the same time,the construction of continuous casting mold flux steady state heat transfer experiment,through the water-cooled copper probe experiment to measure the temperature distribution of the two sides of the mould flux,and then get the comprehensive thermal resistance of different thickness of the slag channel.Numerical simulation results show that when the surface temperature of billet decreases from 1415℃to 1345℃,the liquid mould flux in the upper part of the mould is rapidly thinned from 1.7 mm to 1.04mm,and the total simulated thermal resistance along the direction of billeting is increased from 0.67×10^(-3)m^(2)·K/W to 1.46×10^(-3)m^(2)·K/W.Thermal resistance experiments results show that the integrated thermal resistance obtained from the experiments is smaller than the numerical simulation,and the integrated thermal resistance of the slag channel increases with the increase of the thickness,and the typical value of the thermal resistance is(2.28~7.89)×10^(-4)m^(2)·K/W.