With the increase in the development of CFD based codes for gas-solids flows, the viscous nature of gas-solid behaviour is becoming an increasing important parameter to determine. Generally, the assumption on the viscous behaviour of gas-solid flows is that the viscosity is only related to the interstitial gas rate of deformation rather than the overall gas-solids deformation response. This deformation response can vary from the conveying gas viscosity response for dilute gas-solid systems to apparent gas-solid viscosity behaviour for material that exhibits high air retention. (e.g. fluidised material). The apparent viscosity calculations for an alumina powder were based on the resistance force of a sphere passing vertically through the aerated alumina bed. Initial results of the drag force of the sphere found that the associated Cd of the aerated bed could vary between 0.1 and 2.0 with the aerated alumina bed exhibiting shear thinning (pseudo-plastic) viscosity behaviour.
International Symposium Reliable Flow of Particulate Solids IV (RELPOWFLO IV). Proceedings of the International Symposium Reliable Flow of Particulate Solids IV (RELPOWFLO IV) (Tromso, Norway 10-12 June, 2008) p. 472-477