Density Distribution Evaluation of Free Fall Particles Using CT and State Transition Matrix

Spatial particle density distribution images in a pipe cross section have been evaluated by means of state transition matrix, which is a parameter indicating the dominant particle density transition patterns among time series images consisting of CT 2D-space and 1D-time. State transition characterizes the transition patterns for positions in a cross section as monotonous transitions, sudden transitions, and extreme value transitions. In free fall particles in a vertical pipe, high, sudden and extreme value transitions do not occur, because particle flow rate at this position is low, and therefore the probability of collision among particles is also low. A high, sudden and extreme value transitions occur near the pipe center when the particle flow rate is high, because the probability of collision among particles is high.