Numerical analysis of discrete phase induced effects on a gas flow in a turbulent two-phase free jet

The paper addresses numerical simulation of turbulent two-phase flow in a long vertical tube and turbulent two-phase free jet formed at the tube outlet, analyzing agreement between the numerical results and the results of corresponding experimental investigation carried out earlier. In the numerical analyses conducted, gas phase was modeled as an air flow (having a mass flow-rate in the range of 1.25-4.00 g/s), while the sand particles of two different sizes (0.25-0.30 and 0.8-1.0 mm) represented a discrete phase (particle to gas mass flow ratio of 0.72-4.08) in the two-phase flow considered. Gas-particle interaction was analyzed based on the gas velocities in the particle-laden two-phase flow and the particle-free gas flow, calculated and measured at various locations along the longitudinal axis and radius of the jet. Mathematical model of continuous phase flow was developed based on the single phase flow models, with certain corrections introduced to account for the effects of particles in the flow. In the simulation model developed, the flow analyzed was modeled as a two-phase mixture, with Eulerian simulation used to account for the gas phase behavior and the Lagrangian simulation modeling the particle movement in the two-phase flow considered. In order to appropriately close the system of time-averaged equations, k-epsilon turbulent model, deemed the most reliable, was used. Phase coupling i.e. fluid-particle interaction was modeled using the PSI-CELL concept. The results obtained via numerical simulation have shown a good agreement with the experimental data acquired. (C) 2011 Elsevier Ltd. All rights reserved