- Turbulent flow patterns of dilute gas-particles flows in a vertical pipe are numerically investigated according to the Eulerian-Lagrangian approach by using the k = l model. Calibration of the numerical tools (commercial CFD software (FIDAP 8.6) and additional computer programs) is obtained by confirming the numerical predictions with available experimental results. Additionally, a comparison between the present work and experimental data showed an average deviation of about 3% and a maximum deviation of about 6% (for 0.1 mm particle diameter). The effect of geometrical parameters, flow parameters, and materials characteristics on gas-particles flow behavior were studied. It was observed that an increase in particle diameter, loading ratio, Re number (for constant loading ratio and variable mass flow rate), and particle density increased the acceleration length and the slip velocity. For a constant mass flow rate and variable loading ratio, a higher Re number increased slip velocity but decreased acceleration length. Additionally, it was found that variations in pipe diameter have negligible effect on the acceleration length and slip velocity for constant particle mass flow rate and constant loading ratio.