Research On The Inverse Problem Of Heat Transfer In ASP Continuous Casting Muold

Continuous casting is a widely used production mode in iron and steel production at present.However,the characteristics of thin slab continuous casting,such as high casting speed,large heat flow and large width thickness ratio of slab section,make it easy to have longitudinal cracks on the slab surface and cracks on the copper plate of the mold in the continuous casting process.Relevant research shows that the surface quality of the slab and the life of the mold are closely related to the heat flux density in the mold.The main reason for the crack of the copper plate in the mold is the thermal stress produced by the uneven heating of the copper plate in the mold.Therefore,it is of great significance to study the heat flux density distribution and temperature field distribution in the mold to improve the quality of the slab and extend the life of the mold.Due to the special environment of continuous casting production,the direct detection of accurate heat flow density distribution in the mold is limited by existing detection technologies.Therefore,it is of great practical significance to calculate the heat flux density between the mold and the slab by using the mold and the slab by using the inverse problem of heat transfer based on the temperature data of the thermocouple in the mold.First of all,for ASP thin slab continuous casting mold,a two-dimensional heat transfer positive problem model of mold is established.The finite volume method is used to discrete the calculation area,and MATLAB is used to program the discrete equation,and the correctness of the positive problem model is verified.Secondly,inverse heat transfer model is established by L-M method.Using wavelet analysis to reduce the noise of the temperature measured by the thermocouple installed on the ASP thin slab continuous casting mold.Based on the data after noise reduction,the distribution of heat flux in the mold is inversed.Combining the calculation results with the empirical formula of heat flow density,the heat flow density in the mold is fitted longitudinally,and the overall heat flow density distribution between the mold and the slab is given.Aiming at the L-M method,a new incremental parameter updating method is introduced,which makes the algorithm achieve global convergence,and combines Broyden algorithm to accelerate the convergence speed.Then,numerical simulation experiments are carried out for the influence of thermocouple measurement noise,initial guess of inversion parameters,thermocouple position and copper plate thickness on the calculation results of the inverse mathematical model.Through the established heat transfer inverse problem model,the influence of process parameters such as ASP continuous casting mold blank drawing speed and casting temperature on the heat flux density in the mold is analyzed.Finally,the solidification heat transfer model of the slab in the mold is established.Considering the liquid phase change factors of steel,based on the inverse problem calculation results,using the finite volume method and MATLAB programming to calculate the solidification heat transfer of the slab,the temperature distribution of the slab and the thickness distribution of the slab are solved.The method of solving the thermal resistance between the mold and the slab is given,and the longitudinal distribution of the thermal resistance is calculated to provide a reference for the design of the mold.