Development of a particle resuspension model for a rarefied gas flow

During operation of a large-scale fusion facility, a large amount of metal dust can be generated and deposits on the structure surface on the bottom side of the vacuum vessel. In loss of vacuum accident scenarios the air ingress flow through a breach will mobilize the deposited dust particles and produce a dust cloud, which endangers the safety of the whole fusion facility. Therefore, in the phenomena of dust mobilization, the mechanism of particle resuspension in a rarefied gas flow condition has to be understood fundamentally, in order to estimate the amount of mobilized dust. In the study, a classical force balance model for particle resuspension in a normal condition is extended to the regime of rarefied conditions by correcting the aerodynamic drag force in terms of the specific Knudsen number of the rarefied flow. Based on the model a critical bulk flow velocity for particle resuspension is estimated, which can be further used to predict the percentage of mobilized dust.