The minimum fluid velocity to maintain particles just suspendedwas deduced, and the theoretical analysis shows that the minimumvelocity is influenced by the properties of the solid and liquid, notby the operational co...The minimum fluid velocity to maintain particles just suspendedwas deduced, and the theoretical analysis shows that the minimumvelocity is influenced by the properties of the solid and liquid, notby the operational conditions. For justification, the local minimumvelocity at the bottom of the tank was measured by a bi- electrodeconductivity probe, in a square-sectioned stirred tank (0.75m×0.75×1.0m) with the glass beads-water system. The experiments showed thatthe fluid velocities for the same suspension state were identicaldespite that the power Dissipated per unite mass was not the sameunder different configuration and operation. Both theoreticalanalysis And experimental results indicate that the off-bottomsuspension is controlled by the local fluid flow over the bottom Ofthe stirred tank.展开更多
Tons of solid particles, like carbon, beryllium and tungsten with diameters of several to several hundreds microns, would be generated as dusts in vacuum vessel during operation of ITER, In accident scenarios, e.g., l...Tons of solid particles, like carbon, beryllium and tungsten with diameters of several to several hundreds microns, would be generated as dusts in vacuum vessel during operation of ITER, In accident scenarios, e.g., loss of vacuum accident, the potentially combustible dust particles can be suspended by the air ingress and entrained into the whole vessel, and impose a risk of dust explosions to the whole facility. Therefore, the mechanism of particle resuspension was investigated theoretically. A force balance approach and numerical fittings have been utilized to develop a semi-empirical particle resuspension model based on a group of particle resuspension experimental data. The model has been applied into a three-dimensional computational fluid dynamics code, GASFLOW. The model validation has been done by comparison of the numerical predictions about particle resuspension rates in given incoming flows against the corresponding experimental data. The comparisons have proved the validity of the developed model.展开更多
文摘The minimum fluid velocity to maintain particles just suspendedwas deduced, and the theoretical analysis shows that the minimumvelocity is influenced by the properties of the solid and liquid, notby the operational conditions. For justification, the local minimumvelocity at the bottom of the tank was measured by a bi- electrodeconductivity probe, in a square-sectioned stirred tank (0.75m×0.75×1.0m) with the glass beads-water system. The experiments showed thatthe fluid velocities for the same suspension state were identicaldespite that the power Dissipated per unite mass was not the sameunder different configuration and operation. Both theoreticalanalysis And experimental results indicate that the off-bottomsuspension is controlled by the local fluid flow over the bottom Ofthe stirred tank.
文摘Tons of solid particles, like carbon, beryllium and tungsten with diameters of several to several hundreds microns, would be generated as dusts in vacuum vessel during operation of ITER, In accident scenarios, e.g., loss of vacuum accident, the potentially combustible dust particles can be suspended by the air ingress and entrained into the whole vessel, and impose a risk of dust explosions to the whole facility. Therefore, the mechanism of particle resuspension was investigated theoretically. A force balance approach and numerical fittings have been utilized to develop a semi-empirical particle resuspension model based on a group of particle resuspension experimental data. The model has been applied into a three-dimensional computational fluid dynamics code, GASFLOW. The model validation has been done by comparison of the numerical predictions about particle resuspension rates in given incoming flows against the corresponding experimental data. The comparisons have proved the validity of the developed model.
