MODELING OF TURBULENT GAS-PARTICLE FLOWS IN RISERS: INFLUENCE OF TURBULENCE MODULATION ON THE RADIAL SOLIDS SEGREGATION

摘要

A two-fluid correlated collision model was used to study fully developed turbulent gas-particle flows in risers, where the influence of the gas-phase turbulence on the particle dispersion was taken into account via a gas-particle velocity covariance, which was described with an additional transport equation. The correlated collision model remedied the unrealistic sensitivity to the particle-particle restitution coefficient, which was observed when the gas-solid velocity covariance was ignored. However, the extent of the radial solids segregation was significantly under-predicted, which could be attributed to an over-estimation of the turbulence modulation near the wall. The transition of the dominating mechanism determining the radial solids segregation from gas phase turbulence to particle-particle interactions for systems with larger particles could be well described.