An assessment of steady-state conditions in single slug horizontal pneumatic conveying

This study used a 3D coupled CFD-DEM model to assess how slugs tend towards steady state in single slug horizontal pneumatic conveying. Initial slug length, inlet velocity and initial stationary layer fractions were systematically varied for a total of 72 simulations. Previously made observation that slugs tend towards a steady state was confirmed via a theoretical derivation. The derivation shows that slugs move towards their steady state lengths exponentially. This allowed for a calculation of a characteristic time scale which is a measure of how quickly a slug tends towards the steady state. The theoretical estimate which is a function of slug porosity, steady length, velocity and stationary layer fraction has good agreement with simulated results. A link between steady slug length and solids loading ratio was also shown. (c) 2021 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.