Analysis of heat transfer through the casting‐mould interface including gas‐gap effect and application to TiAl castings

Abstract

Purpose -The purpose of this paper is to describe how a 3D/1D transient heat transfer model has been developed for getting accurate thermal boundary conditions when investigating the heat transfer in the TiAl castings and also for reducing the computational cost and simplifying the mesh generation. Design/methodology/approach -Heat transfer in the mould is assumed to take place only in a direction perpendicular to the mould wall, called 1D heat transfer. The coordinates of cell centre and the temperature in the mould wall can be calculated by the model instead of meshing mould. Heat transfer in the mould is computed via the FD solution of a 1D heat transfer equation. Findings -For some types of geometry, the model works very well. However, for some, which contain the geometric feature called "dead corner", the model can't cover. There is some impact on the accuracy of the model. Practical implications -In the casting industry, the geometry of the casting is usually very complex and contains different features. This leads to difficult meshing when using numerical model to predict the casting process. Furthermore, an accurate calculation is very important on the thermal boundary during filling and solidification, to support practice, to improve the process and minimise the casting defects. Originality/value -In this paper, a novel method is developed to calculate the heat transfer through the casting-mould interface to the mould wall in a casting.

Numerical modeling of heat transfer through casting–mould with 3D/1D patched transient heat transfer model

“…The effect of 'dead corner' does not reach so far. At C2, the temperature curve using 3D/1D model presents large deviation from that with PHYSICA 3D model as shown in previous study [17]. It is noted that the temperature curve with 3D/1D patched model is closer to that with PHYSICA 3D.…”

“…Through the casting-mould interface and the mould wall, the 3D/1D model has been developed to calculate the heat transfer. The details about the 3D/1D model are presented in [17]. Fig.…”

“…1b and c, a 'dead corner' is identified where the 3D/1D model cannot cover. The 'dead corner' effect will result in low accuracy of heat boundary at the metal-mould interface reported in [17].…”

“…Researchers have been numerically and experimentally studied the effect of gap on heat transfer for different alloys [13][14][15][16]. We calculated the heat transfer across the casting-mould interface by 3D/1D model including the effect of air gap [17]. It was showed that there was a 'dead corner' for some geometry where the 3D/1D model cannot cover it.…”