2017 Volume 103 Issue 12 Pages 755-762
Heat transfer analyses of casting processes offer an effective way of understanding solidification processes which is important for prevention of formation of casting defects and for control of segregations. The accuracy of the simulations depends on the accuracy of input parameters such as thermal conductivity and heat transfer coefficient. It is not straightforward to evaluate such parameters, especially thermal conductivities of bulks and heat transfer coefficient with high accuracy. It is very important to develop a reliable method for estimation of these parameters. In this study, particle filter, which is a method of data assimilation, is applied to estimation of thermal conductivity of melt and heat transfer coefficient during alloy solidification in mold casting and its applicability is systematically investigated on the basis of twin experiments. It is shown that a constant heat transfer coefficient can be accurately estimated in this method by utilizing a single cooling curve measured in the mold or in the melt near the mold, while the thermal conductivity can be accurately estimated from a single cooling curve measured in the melt. In addition, this method can be utilized for estimation of time-dependent heat transfer coefficient without any assumption and/or approximation on its time dependence. Importantly, the thermal conductivity and time-dependent heat transfer coefficient can be estimated simultaneously with high accuracy.
