Characterization of Heat Transport and Diffusion Processes During Metal Melt Filtration

Abstract

This chapter contains a summary of thermodynamic investigations of ceramic filters, metal melts and their interaction, which can serve as a basis for the optimization of the filters as well as the casting and metal melt filtration process. First, the thermophysical properties of two different filter base materials are briefly discussed. Subsequently, after demonstrating measurement conditions and parameters, the effective thermal conductivities of filters with varying pore size, porosity and material measured by the Transient-Plane-Source method at temperatures up to 700 °C are presented. The experimental determination of radiative properties of the filters using a Fourier-transform infrared spectrometer with an external integrating sphere was compared to simple predictive methods. Finally, after performing experiments with air, a measurement section was created and further developed to determine the volumetric heat transfer coefficient during metal melt filtration. The first results obtained with aluminum melt are presented.In addition to the knowledge of heat transport processes, the understanding of the sorption and diffusion behavior of various gases in metal melts is important. Therefore, a thermogravimetric apparatus, which enables the direct determination of the mass changes caused by (ab-)sorption using a high-precision magnetic suspension balance, was modified especially for this measurement task.