Study On The Inverse Heat Transfer Problem Of Inner Wall Shape Of Blast Furnace Bosh

The blast furnace is an important equipment of ironmaking process.The bosh is located in the high heat load zone of the blast furnace,and the shape of the inner wall changes with the change of the furnace condition.The lining of the blast furnace is eroded during a period of time after blowing-in,and then the slag skin is formed on the surface of the cooling stave.The production of blast furnace is seriously affected by the excessive thickening and frequent shedding of slag skin.But it is difficult to measure the change of blast furnace inner wall directly.In this paper,the temperature data measured by the thermocouple embedded in the wall are used to calculate the temperature field of the bosh by the research method of inverse heat transfer,which can realize the monitoring of the inner wall shape and provide the theoretical guidance for the operation of the blast furnace,and extend service life.Considering the phase transformation and contact thermal resistance of slag skin during solidification,the model of blast furnace bosh heat transfer is established.The inner node method is used to mesh the model,and the finite-volume method is used to discretize the heat differential equation.The direct heat transfer problem model is solved by programming.Taking the solidification process of Al-4.5%Cu alloy as an example,the offsets of solid and liquid phase lines in the model are obtained by solving the direct heat transfer problem.The accuracy of the direct heat transfer problem model is verified.The inverse heat transfer model of blast furnace bosh is established.Considering the global property of PSO(Particle Swarm Optimization)algorithm and the fast convergence of L-M(Levenberg-Marquardt)algorithm,PSO-LM hybrid optimization algorithm is used to solve the inverse heat transfer problem model of furnace bosh,and the boundary heat flux and contact resistance are obtained.The results of inverse problem are substituted into the direct problem model to obtain the temperature field and the change of the inner wall shape of the furnace bosh.The temperature of the thermocouple position in the inverse temperature field is extracted and compared with the measured temperature,and the relative root mean square difference is calculated,which verifies the accuracy of the inverse heat transfer model.The influence of the position of thermocouple,the Biot number and the noise of temperature measurement on the solution of inverse heat transfer problem of blast furnace bosh is analyzed.The results show that the position of thermocouple has little influence on the solution when the Biot number is small,but has great influence on the solution when the Biot number is large,and the noise of temperature measurement has a significant effect on the solution.