Evaluation of heat transfer coefficients in continuous casting under large disturbance by weighted least squares Levenberg-Marquardt method

The work presented in this paper focuses on estimation of heat transfer coefficients with measured surface temperature containing large disturbance. By using measured surface temperature, the heat transfer coefficients can be calculated. However, measured surface temperature always contains uncertainty or large disturbance. Those uncertainty and large disturbance may lead to an inaccurate result of heat transfer coefficients. To address the above problem, this paper proposes an integrated approach which combines WLS (weighted least squares) with modified LM (Levenberg-Marquardt) method. Moreover, the SAE 1007 billet is used to illustrate the validity of this integrated approach. The experiment results show that WLS-LM method can overcome the influence of large disturbance on the results. Finally, the corrected heat transfer coefficients are used to improve the accuracy of the heat transfer model, which can be applied to predicting the solidified shell thickness of billets, and the predicted results are confirmed by the actual industrial data.