二成分系流動層内の気泡と粗大粒子挙動の可視化

Abstract

Fluidized-bed combustion systems are composed of many kinds of particles with a variety of sizes, e.g. coal, sand, RDF, limestone etc. In such a binary system of particles, the segregation, if occurs, may harm the combustion, mixing and heat transfer in the bed, depending on the particle movement. The particle movement or circulation in the fluidized-bed depends on many factors, such as the density ratio, size ratio, shape of particle, fluidization velocity. Owing to the difficulty of flow visualization, such particle movement has not been fully understood so far. This paper describes large-particle movement obtained by the flow visualization using neutron radiography. Tracer particles mixed into the fluidized particles indicated clearly bubbles and the cloud behavior around the bubble. Image processing, i.e. PIV and PTV, gives rather clear understanding on the interaction between the large particle, emulsion and/or cloud behavior in the bed.