A common feature of multiphase flows is the existence of very different flow patterns, which makes modeling much more complicated. In the case of the transport of large solid particles by a carrying liquid, several intermittent, stratified and dispersed regimes are observed in horizontal and inclined flows [1,2,4,17]. For the specific case of vertical ascending flows, though plug or slug flows are observed in the pneumatic transport of small particles[18] to the best of our knowledge only dispersed regimes are observed for the hydraulic transport of large ( dp P1 mm) and massive ( s P1.5) particles [2,9–11] . The present section first presents a model for vertical ascending flows and then the typical regimes that are encountered in the horizontal experiment and the different possible models.