Effects of temperature,solid particle size and concentration on wall slip behavior of coal-water slurry in pipelines
By changing pipe diameter,temperature,solid particle size and concentration,slip flow behavior of coal-water slurries in pipelines was investigated on a pilot scale flow facility.A procedure combining the traditional Mooney slip-correction method with numerical technique based on Tikhonov regularization was used to determine wall-slip behavior.The results suggested that when temperature and solid particle size increased,critical shear stress decreased and slip velocity increased significantly.At a high concentration,there were larger critical shear stress and higher wall shear stress needed to yield the same slip velocity than low concentration slurry.Increasing temperature at a higher concentration resulted in rapid decrease in critical shear stress and yield stress.Slippage contribution depended mainly on the difference between yield stress and critical shear stress at low wall shear stress,and on both wall-slip velocity and rheological behavior of bulk slurry at high wall shear stress.