A particle impact probe for hydrodynamic studies in fluidized beds

Abstract

This paper describes the development and testing of an instrumentation system used to monitor the dynamic behavior of particles in fluidized beds with minimum disturbance of particle motion. The monitoring system includes a particle impact probe and supporting electronics for probe excitation and data treatment and storage. The probe and electronic system can measure the x, y, and z components of momentum transferred to the probe head by individual 700- and 3 200-micrometer particle impacts spaced more than 500 micro-seconds apart. When calibated, the monitoring system can also measure the x, y and z components of solids force exerted on the probe head in dense fluidized beds. The prototype probe has a 0.318-centimter outside diameter, 7.62-centimeter long, stainless steel tube base with a 0.318-centimeter diameter nylon sphere probe head mounted at one end. When impacted by particles in a 15.3-centimeter diameter fluidized bed, the probe head produced xyz three-axis motion in a miniature electrode system mounted within the tube base. The signals produced by the electrode system were calibrated to produce either the components of the momentum vector of the probe head during individual particle impacts or the three components of the force exerted on the probe head during multiple, closely spaced particle impacts.