Since the pneumatic conveying performance of granular materials in the transition zone between dilute- phase and dense-phase still lacks full understanding and assessment, especially the mechanism for the formation of unstable flow, tests have been carried out on poly pellets (particle diameter = 4.7 mm, particle density = 897 kg/m3) and two different stainless steel pipelines (60.3 and 98.4 mm ID, each 21 m long). By careful observation and analysis of flow behaviours (covering dilute-phase, unstable zone and low-velocity slug-flow), five different flow modes (as the air velocity is decreased): fully suspended flow; strand flow; stable or unstable strand flow over a stationary layer for low solid mass flow rates; strand flow over a slowly moving bed for high solid mass flow rates; low-velocity slug-flow are identified. The mechanism involved in the formation of unstable zone was explored.
History
Citation
Yi, J, Wypych, PW & Hastie, DB, Mechanism for Unstable Pneumatic Conveying of Granular Materials through Horizontal Pipe, Bulk Materials Storage, Handling and Transportation Conference Proceedings Vol 2, 2001, p 907-915, Canberra, Australia: The Institution of Engineers, Australia.