Modeling of viscosity and heat transfer of complex oxidic melts in WECHSL

摘要

Attention has recently been drawn to the importance of the melt properties, among others the viscosity of oxidic melts, on the heat transfer and on the melt behaviour during MCCI. In the first step the viscosity model in WECHSL was changed in order to achieve a better agreement between the available viscosity measurements and the viscosities predicted by WECHSL. In order to account for the variation of the viscosity with temperature an iterative scheme was used in WECHSL to determine the temperature gradient of the pool bulk temperature to the interface temperature. In addition, the influence of porosity of the melt on the thermal conductivity was modeled. Finally, the so-called property ratio method was implemented for correcting the Nusselt number. A validation matrix which consists of the ACE and SURC experiments was used to assess the improvements of the code. (orig.)