Suspension stability of slurry Taylor flow: A theoretical analysis

- First study to theoretically predict the suspension stability of slurry Taylor flow.
- A force balance mode is developed between particle, bubble and channel wall.
- Critical values of operating conditions and particle properties are identified.
- Device of slurry Taylor flow could be used to achieve efficient particle selection.

A theoretical model for predicting the suspension stability of slurry Taylor flow is presented. Force balance analysis is conducted on a particle that moves downward along the leading meniscus of a Taylor bubble towards the thin liquid film between the bubble and the channel wall. The concept of maximum resistance force is proposed for calculating critical values of capillary number, particle size and density, and contact angle that determine whether solid particles stay suspended in the same liquid slug or fall through the thin liquid film and travel among different liquid slugs. It was found that the deformation of bubble surface enforced by the particle motion appeared independent of the particle material that has rough surface. The maximum capillary force decreased as the capillary number increased, but increased faster than the downward drag force as the particle size increased. A particle with relatively more hydrophobic surface was more prone to fall into the liquid film. It was implied that devices of Taylor flow might be applied to achieve particle selection based on particle size, density and surface hydrophobicity. The model proves capable of accurately predicting the suspension stability of slurry Taylor flow for the design and operation of industrial chemical reaction processes.

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