MEASUREMENT OF LOCAL PARTICLE VELOCITIES AND VELOCITY DISTRIBUTIONS IN GAS-SOLID FLOWS BY MEANS OF THE SPATIAL FILTER METHOD

Spatial filters provide a method of measuring velocities optically. Ap plication of this method for particle velocity measurement in two-phas e systems with high solids loadings requires the use of a probe to rea ch different positions inside the flow. After a comparison with other methods, different realizations of spatial filter velocimeters are pre sented. One such velocimeter involves the use of a CCD (charge coupled device) line sensor. The design of this probe for measurements inside a circulating fluidized bed riser with a diameter of 0.4 m is discuss ed. Special attention is given to the problem of flowing particles inf luencing the optical window of the probe, and the properties of two di fferent kinds of probes are compared. Results of measurements from one of the probes are presented, which prove its usefulness for the desir ed application. (C) 1997 Elsevier Science S.A.