Estimation of permeability and Forchheimer coefficient for non-uniform packed beds

Sano, Yoshihiko*; Ota, Kensuke*; Kuwahara, Fujio*; Uesawa, Shinichiro  ; Yoshida, Hiroyuki  

To estimate the thermal behavior of fuel debris inside the Primary Containment Vessels (PCVs) of TEPCO's Fukushima Daiichi nuclear power station, a simulation method has been developed using the JUPITER code with porous medium models. However, it has been found that the selection of models and parameters according to the internal structure of the porous media significantly affects the accuracy of simulation results, highlighting the need for appropriate model selection strategies. In this study, we investigated methods for calculating macroscopic model constants that characterize flow behavior in porous media. These properties are influenced not only by the volume ratio of solid and gas phases but also by the structural features of the porous media. Focusing on packed beds composed of particles with varying diameters, we conducted numerical simulations to evaluate permeability and Forchheimer coefficient across diverse structural configurations. Based on the results, we propose a method for appropriately determining these parameters according to the structure of the packed bed, thereby contributing to the improvement of the porous media heat transfer and flow model.