Dynamics of fluidized-bed reactors. Development and application of a new multi-fiber optical probe

There seems to be no method available to measure all parameters of interest s in multiphase flow systems with high solids concentration and with reason able accuracy. Parameters include, local particle velocity vectors, solids volume fractions and bubble rise velocity, size, frequency and volume fract ion. In this study a novel method based on a fiber optical technique and tr acer particles has been developed for simultaneous measurements of the ment ioned local flow properties in highly concentrated multiphase flow systems such as gas-solid fluidized bed reactors. A particle present in the measuri ng volume in front of the probe is marked with a fluorescent dye. A light s ource illuminates the particles and the detecting fibres receive reflected light from uncoated particles and fluorescent light from the tracer particl e. Using optical filters, the fluorescent light can be distinguished and to gether with a small fraction of background light from uncoated particles ca n be used for the determination of local flow properties. The method gives the possibility for simultaneous measurement of the local movement of a sin gle tracer particle, local bubble properties and the local solids volume fr actions in different positions in the bed. (C) 1999 Elsevier Science Ltd. A ll rights reserved.