Optimal placement of probes for dynamic pressure measurements in large-scale fluidized beds
Journal article, 2004

Pressure data sampled at sufficiently high frequency (typically 20 Hz or higher) can yield much information about the hydrodynamic state of a fluidized bed. Since part of the pressure waves travelling through large (industrial) fluidized beds is only detectable in a limited area of the bed, pressure measurements need to be performed at several positions to cover the whole bed. We examine these local pressure waves (caused by, e.g., passing bubbles or coalescing bubbles) in a 0.80 m i.d. bubbling fluidized bed of Geldart B particles. Experiments and simulations are performed to determine the intensity decrease as local pressure waves propagate from their origin. A new spectral method is applied to determine the degree of coherence for pressure signals measured at two different positions in a fluidized bed. For a superficial gas velocity of 5u(mf), local pressure waves can be detected up to a radial distance of about 0.5 m from their origin; this distance is somewhat lower for lower gas velocities. This means that the radial spacing of pressure probes should not exceed 1 m. For large diameter beds with a bed height below 1.5 m, a set of probes at a single level and at several radial positions is sufficient to observe or monitor the dynamic state of the complete bed; the probes should preferably be placed at a height of 30% to 40% of the total bed height.

industrial installations


pressure measurements

gas-solid fluidized beds

pressure probe spacing

pressure fluctuations


J.R. van Ommen

Delft University of Technology

J. van der Schaaf

Eindhoven University of Technology

J.C. Schouten

Eindhoven University of Technology

Berend van Wachem

Chalmers, Department of Thermo and Fluid Dynamics

Chalmers, Applied Mechanics

M.O. Coppens

Delft University of Technology

C.M. van den Bleek

Delft University of Technology

Powder Technology

0032-5910 (ISSN)

Vol. 139 3 264-276

Subject Categories

Chemical Engineering

Fluid Mechanics and Acoustics



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