Flow characteristics for solid-liquid two phase flow using particles with lower density than that of liquid

Flow characteristics were experimentally examined for solid-liquid two-phase flow using particles with lower density than that of liquid. Three flow directions, i.e. the horizontal flow, upflow and downflow, were utilized. In the horizontal flow, the particles flowed in the upper side of the tube, contacting the pipe wall. In the upflow, they were concentrated at the pipe wall while in the downflow they were flocked at the pipe center. At a relatively low mean velocity, the pressure loss was higher in the horizontal flow and downflow, but it was lower in the upflow than that in the case of liquid flow. As the velocity increased, the pressure loss in each flow direction approached to that in the case of liquid flow.