(11d) The Effect of Fluid on Particles Conveying in Pipes

Pneumatic conveying (PC) and hydraulic conveying (HC) have significant applications in various industries. These two ways of conveying differ only by the type of the carrier fluid, one is compressible and the other is not. Even so, these two ways of conveying considered very different attracting different research groups rarely having a dialog. Therefore, one of the main objectives of our ongoing research is to compare both systems and bridge the gap to found common analysis for both PC and HC.

Pneumatic conveying is basically analyzed by showing a measured phase diagram or state diagram (Zenz diagram). The diagram presents the steady-state pressure drop per length of pipe versus the superficial gas velocity. Each line presents a constant particle mass flow rate. Hydraulic conveying of larger particles is called heterogeneous flow or settling flow where the flow is treated as two-phase flow as for PC. In such a case, it is common to analyze the flow by a similar phase diagram. However, there are a number of differences:

1. Instead of pressure drop, head loss is presented.

2. Instead of superficial fluid velocity, mix velocity is presented.

3. Instead of lines of constant solid flow rate, lines of constant volumetric concentration are presented.

In order to bridge the gap between PC and HC we designed a new feeder for HC based on PC technology, thus, a rotary valve feeder. This enabled to control the particle mass flow rate and to measure the liquid superficial velocity. This presentation will present the new design and compare phase diagrams for the same particulate materials conveyed in various fluids (air, water and brine).