Study On The Inverse Heat Transfer Problem Of Lining Of Blast Furnace Hearth

The hearth is the key part of the blast furnace.During the production,the lining of the hearth is under the extreme conditions of high temperature and high pressure.It is also subject to the erosion of high temperature molten iron and other alkali metals.In the past,the lining of the hearth will be Damaged to varying degrees,if the lining of the hearth is severely eroded,it is prone to burnout and other accidents,which not only causes danger but also causes huge economic losses.Therefore,the health of the hearth determines the service life of the blast furnace.However,in the normal working state of the blast furnace,it is impossible to directly measure the thickness of the lining of the hearth.For this reason,the internal working state of the hearth can be studied by numerical simulation,through the thermocouple installed inside the hearth.The measured temperature data using the heat transfer inverse problem method can accurately calculate the real-time heat flux density distribution in the hearth and the variation of the thickness of the hearth lining.According to the calculation results,the judgment of the health status of the hearth can avoid dangerous accidents happen.Considering the phase change factor of molten iron in the hearth and the influence of contact thermal resistance,the mathematical model of the heat transfer problem of the blast furnace hearth is established.The model is meshed by the internal node method,and the differential equation is discretized by the finite volume method.Programming solve.Taking the unidirectional solidification process of Al-4.5%Cu alloy as an example,the results calculated by the program are consistent with the previous research results,thus verifying the correctness of the mathematical model of the positive problem established.Based on the L-M method,the mathematical model of the heat transfer inverse problem of the blast furnace hearth is established.The heat flow boundary condition,contact thermal resistance and thickness of the hearth lining of the hearth are calculated through the inverse numerical calculation of the inverse problem,and the temperature field distribution in the hearth is obtained.By comparing with the actual measured temperature data of the thermocouple,the accuracy of the inverse problem mathematical model is verified,and the accuracy of the inverse problem calculation result is evaluated by the relative root mean square difference.The influence of the temperature data measured by thermocouples at different locations,the measurement noise of the working environment and the Biot number on the calculation results of the heat transfer inverse problem of the blast furnace hearth are analyzed.It is concluded that the temperature measurement data of the thermocouples at different locations have no effect on the calculation results of the inverse problem;Measurement noise affects the accuracy of the inverse problem calculation results without affecting its stability;different Biot numbers have a greater impact on the inverse problem calculation results.