Dynamic behaviour of a vibrated fluidized bed of fine powders

The dynamics of a fully fluidized bed of group A powders subject to vertical vibration was studied in a 85 mm ID transparent perspex column. Acceleration level was set to a/g = 1. Frequency was varied in the range between 5 and 50 Hz. Different bed mass values corresponding to different bed heights were tested. In this work the dynamic response of the fluidized to imparted vibration was assessed by direct observation of the fluctuation of the bed height. Time series of the position of the oscillating column wall and those of the oscillating bed height were obtained by means of particle image velocimetry applied to sequences of digitised images of the bed taken with the help of a high speed video camera. These time series were compared with a theoretical model which assumes the bed as a linear elastic continuum subject to viscous damping