Pressure drop in loop pipe flow of fresh cemented coal gangue-fly ash slurry: Experiment and simulation

Cemented coal gangue-fly ash (CGF) mixtures are made by mixing cement, coal gangue, fly ash and water, and the CGFs are commonly used as the backfill materials for filling underground voids in coal mines. Generally, pipeline slurry transportation system is constructed to deliver the CGF into the underground, and pressure drop is one of the most significant technical indicators needs to be considered in designing the pipeline slurry transportation system. Therefore, a test loop system is employed to investigate the pressure drops of CGF slurries with different mix proportions. Based on the experimentally determined flow properties of the CGF slurry, a pipe flow model for predicting the flow behavior of the CGF slurry in the pipe loop is developed. This model is put into COMSOL Multiphysics to carry out simulation work, and then the simulation outcomes are compared with loop testing results. The favorable agreement between the model simulation and the loop test indicates that the developed model is valid and can be available to conduct further simulation exercise. By means of numerical simulation, effects of slurry volumetric flow rate and pumping pressure, as well as the combined effect of pipe inner diameter and flow velocity on pressure drop in the pipe loop flow of fresh CGF slurry are demonstrated. The obtained results in this study are helpful to the design of a practical CGF slurry pipeline transportation system, as well as to the selection of an appropriate pump capability. (C) 2015 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.