APPLICATION OF FIBER OPTIC REFLECTION PROBES TO THE MEASUREMENT OF LOCAL PARTICLE-VELOCITY AND CONCENTRATION IN GAS-SOLID FLOW

New, technically sophisticated measurement techniques must not be used blindly. In order to ensure accurate measurements, the limits of such devices must be well known. In this study a single-fiber optic reflec tion probe was thoroughly tested in two-phase gas-solid flows for the measurement of particle velocity and concentration. A novel, dynamic c alibration procedure for particle concentration measurements has been proposed and tested in the downflow reactor section of a pilot-scale c irculating fluidized bed. The results show that, as a particle concent ration measuring device, the probe is very sensitive to electrostatic effects in the flow medium. The velocity measurements are relatively u naffected and were shown to be reproducible with errors of between 10 and 15% for particle velocities of up to 8 m/s.