Applying inverse technique for identification of thermal resistance between cast and mould during permanent casting of metals

摘要

Identification of thermal resistance between cast and mould during permanent casting of metals is the subject of present paper. Mathematically analyzed oundary problem of heat conduction belongs to the group of inverse problems. In verse problems belong to the class of ill posed problems. It means, that solution of the problem is usually extremently sensitive on inaccuracies of input data, e.g. measurements errors. To stabilize the solution, special mathematical techniques have to be applied. Sevedral method are used to stabilize solution of inverse problems. The most widely used are rgularization method and the least squares methods. Presented work shows the possibility of applying of the least squares adjustment methods for identification of boundary transient heat fluxes and temperature within the body. Two versions of the method: standard and with a priori data are analyzed. Second method was effectively used for claculation of thermal resistance between cast and mould during permanent casting of aluminum alloys. Temperature measurements come from the experiments with the solidification of several grades of aluminum alloys. Different thickness of the cast and different kinds of mould coating were anlayzed. Several other factors (for example a mould preheating) was also considered. Influence of the analyzed parameters on the process of solidification during permanent casting is discussed.