Flow Regimes and Regime Transitions

The flow pattern in a horizontal gas-solid pipe flow varies with the solids concentration. In a horizontal pipe flow at a given gas flow rate, the following flow patterns sequentially occur as the particle loading, defined as the mass flow ratio of particles to gas, increases  

Relative motion between particles Large Small 

Apparent particle viscosity Due to gas-particle interaction Due to particle-particle interaction and gas-particle interaction 

Flow regime in applications Steady, turbulent Pseudolaminar to unsteady and stratified 

Motion above minimum transport velocity Stable Unstable 

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