Experimental flow characterization of sand particles for pneumatic transport in horizontal circular pipes

Abstract

This work presents an experimental study carried out to simulate characteristics of turbulent air-sand particles flow through transparent horizontal pipes with various flow conditions. Experimental analysis focuses on the determination of critical pickup velocity of the solid particles from the horizontal sand layers. Mainly the effects of layer height and pipe diameter on the pickup velocity are investigated. Critical pickup velocity is determined by extrapolating the weight loss curves plotted as a function of corrected velocity above the sand layer. Experimental results show significant effects of layer height and pipe diameter on the pickup velocity. Saltation velocity and dune formation mechanisms are also discussed. Critical pick up velocity of solid particles is found to increase with increasing blockage ratio and pipe diameter. Inclination angle for larger sand bed heights caused leading edge effect on air flow entering the reduced cross sectional area above the layer. Sand particles pickup rate is found to decrease with time as a consequence of decreasing layer height. Experimental results have been correlated and compared with previous studies.