Use of pressure fluctuations to validate hydrodynamic similitude in fluidized media: bubbling beds

Principles of dynamic similitude have been used over the last few years to develop hydrodynamic scaling laws for fluidized beds. The present study is a comprehensive evaluation of dynamic scaling in bubbling fluidized beds using pressure fluctuation data from model and prototype beds for 27 distinct operating conditions. Pressure spectra were quantitatively compared by presenting the data as Bode plots and analyzing the plots as linear, dynamical systems. Characteristic frequencies and damping constants for up to three oscillatory phenomena were determined from the Bode plots and compared between model and prototype beds. Comparison of pressure fluctuations between model and prototype bubbling fluidized beds suggest that hydrodynamic similitude can be achieved for a wide range of operating conditions. However, measurements should be made away from the surface of the bed and caution should be exercised in using very small diameter tubes for the model bed.