Application of CT-Processing to Neutron Radiography Imaging of a Fluidized-Bed

摘要

CT-processing is very effective in obtaining 3-dimen-sional information for industrial instruments,and several trials have also been applied to fluidized-beds.In the CT-processing of fluidized-beds,X-rays are used mainly because they are readily availability.Similar processing can be performed by neutron-rays which penetrate most metals,but not some chemical substances,such as hydrogen,boron,gadolinium,which are opaque to the neutrons.Due to these unique characteristics,neutron radiography can be considered as a suitable visualization method of actual industrial instruments made of metal.Thus,neutron radiography also has significant advantages for the visualization of fluidizedbeds.However,neutron radiography requires a nuclear reactor or an accelerator as the neutron source in order to obtain high quality images,which means that the real time CT-processing of multiphase flows by neutron radiography is quite difficult.Consequently,CT-images in this investigation were reconstructed by using time-averaged visualization images.Although time averaging makes the understanding of the void movement difficult,3-dimensional characteristics of the void fraction propagation in fluidized-beds could be clearly visualized by using test sections with significant non-uniformity of the fluidized-gas distribution.