Développement d'un tomographe pour la visualisation des écoulements polyphasiques

Multiphase reactors are widely used in petroleum, petrochemical and biochemical industries. In the present work, a new third generation gamma-ray transmission scanner to measure density distribution across multiphase reactors was developed. Measurements were validated with objects of known dimensions. In this new configuration, the experimental setup was modified from its previous configuration (Lepage, 1997) by installing a sector table over the main rotating table. Seven 2 inch NaI(Tl) detectors are installed over the sector table which moves independently of the main rotating table with a step motor. This configuration allowed us to simulate 10 to 15 times the number of detectors.

The images are reconstructed from the experimental measurements using two types of Matlab reconstruction algorithms: Ifanbeam (filtered backprojection) and Tomplex (iterative least-square technique) which was developed for our specific configuration. The experiments of the validation step are conducted with a known dimensions object (air-water system). Experimental investigations are then conducted in a spouted bed reactor, and flow images obtained with both reconstruction methods of 2mm pixel size (spatial resolution) are compared.