(321c) Experimental Studies of Solid-Liquid Pipe Flow Using LDV

Mixtures of liquid and solids are present in many engineering and geological processes such as hydraulic conveying, energy conversion and the consolidation of soil sediments. Although they are widespread, our understanding of their fluid mechanics behavior is not complete partly due to a lack of experimental data. This data is needed for the development of engineering models that can optimize industrial operations, reduce energy demands and predict undesirable processes like sedimentation in transport lines.

The present investigation obtained novel experimental data for solid-liquid turbulent dilute flows in the intermediate and inertia dominated regime as characterized by the Stokes number. Velocity profiles for each phase and for the three velocity components were acquired in a pilot scale facility using Laser Doppler Velocimetry (LDV) for flows with particles up to 5 mm in diameter at concentrations from 0.7-2% V/V. In general, the presence of the particles flattened the mean liquid profile and augmented the turbulence intensity in the core region of the pipe. The mean particle profile is much flatter than the fluid with a maximum relative velocity at the center. The particle fluctuation profile is much flatter than the fluid suggesting a fairly uniform solid volume fraction across the pipe. The effect of the Reynolds number is marked with fluctuations being reduced with increasing Reynolds numbers.