Airslide flows, Part 1--Experiments, review and extension
Résumé
Airslides are commonly used to transport dry particulate materials over distances as long as 1 km. Air is pumped through the porous bed of the transport channel to fluidize the granular material and to promote the flow down very small bed slopes. Current design of airslides is based on empirical design charts and past experiences. The present paper is the first of a two-part investigation of airslides. It reviews selected experimental studies of airslides with the goal of identifying characteristic features of these flows that we attempt to model in the numerical simulations described in the second companion paper. The experiments of Botterill and Bessant (1976) and a power-law, non-Newtonian finite element model that gave a good representation of the Botterill and Bessant (1976) velocity profiles are described. The McGill fluidized solids channel experimental setup and the associated measurements carried out by Liot (1979) and Chan (1979) are outlined. Some of these results were interpreted by means of simple, hydraulics type backwater analyses. As with the usual hydraulics type open channel flows, it was found that fully developed, uniform depth, granular airslide flows could develop. This is an important observation and it will be used as justification for the methodology employed in the calculations in the companion paper which proceeds to simulate fully developed, three-dimensional fluidized granular flows in a rectangular channel. The distinctive features identified in the review of the airslide flow experiments are summarized.