Thermophysical Properties of Liquid Zirconia Measured by Aerodynamic Levitation at High Temperature

In the frame of severe accident modeling, the knowledge of the so-called-corium thermophysical properties is crucial to obtain reliable simulation. In this work, an aerodynamic levitation technique was used to measure simultaneously surface tension, density and viscosity of liquid zirconia, one phase of corium, at temperature ranging from melting point 2 715 & DEG;C to 2 900 & DEG;C using acoustic excitation. The volume estimation, initially based on the hypothesis of a spherical shape for the sample, was improved with the use of a second camera placed on top of the sample. This enabled a more precise determination of the volume to estimate density. An original post-treatment method was developed to obtain the surface tension by taking into account multimodal oscillation frequencies. The viscosity may be slightly overestimated due to the multimode oscillation. Measurement uncertainties are estimated based on propagation law for the three thermophysical properties considered.

Automated summary

An aerodynamic levitation technique was used to measure the surface tension, density, and viscosity of liquid zirconia, a phase of corium, at temperatures ranging from 2,715°C to 2,900°C. A second camera placed on top of the sample improved the volume estimation, allowing for a more precise determination of density. A novel post-treatment method was developed to obtain surface tension by considering multimodal oscillation frequencies. The viscosity may be slightly overestimated due to the multimode oscillation. Measurement uncertainties were estimated for all three thermophysical properties.