Department of Chemical Engineering, Isfahan University of Technology, Isfahan, I.R. IRAN
Computational Fluid Dynamics (CFD) simulations of gas-solid flow through a positive low-pressure pneumatic conveyor were performed using Eulerian-Eulerian framework. Pressure drop in pneumatic conveying pipelines, creation and destruction of plugs along the horizontal and vertical pipes, effect of 90° elbows and U-bends on cross-section concentrations, and rope formation and dispersion were numerically investigated for the wheat particles at ten different operating conditions. The effects of air inlet velocity and the conveying capacity on the flow behavior were also discussed. Both parameters played a significant role in the conveying flow pattern and also the pressure drop. The numerical simulations validated against the experimental data from literature and also qualitatively compared with trends in experimental data. Excellent quantitative agreement between experimental and simulated results (±1%) was observed in dense-phase conveying. For the dilute-phase conveying simulations underestimated the values of pressure drop by 20%; however, this still falls within the acceptable error ranges reported in the literature. This study stresses the capability of CFD to explain and predict the behavior of complex gas-solid conveying systems and to be used productively for investigations in pneumatic conveying of agricultural and pharmaceutical particles as an aid in the system design..