confirmed in large scale experiments by Sellgren and Addie
[ 3] where they demonstrated the feasibility of waste rock
pumping with dry deposition and recirculation of water and
sand particles.
The transportation of solids in horizontal pipes may be
conceptually divided into fully-stratified, partially-stratified
and fully-suspended flow as first suggested by Newitt et al.
[4]. Transport of contact load solids, that is, when fluid
support mechanisms can be neglected, is only possible when
the mechanical friction between solids and pipe is overcome
and gives rise to large friction losses due to the solids. Upon
increasing the velocity, the 'threshold' of turbulent suspen-
sion of particles is reached. An increase in the amount of
suspended particles with increasing velocity, beyond the sus-
pension threshold, leads to the successive decrease in friction
losses due to the solids. The relative influence of suspended
and non-suspended portions varies and there is no distinct
point at which the flow changes to fully-stratified or fully-
suspended flow. Partially-stratified flow conditions generally
correspond to transportation of sand with mean sizes of about
0.2-2 ram, at velocities of industrial interest in 0.1-0.5 m i.d.
pipelines. Products with rather narrow particle size distribu
confirmed in large scale experiments by Sellgren and Addie [ 3] where they demonstrated the feasibility of waste rock pumping with dry deposition and recirculation of water and sand particles. The transportation of solids in horizontal pipes may be conceptually divided into fully-stratified, partially-stratified and fully-suspended flow as first suggested by Newitt et al. [4]. Transport of contact load solids, that is, when fluid support mechanisms can be neglected, is only possible when the mechanical friction between solids and pipe is overcome and gives rise to large friction losses due to the solids. Upon increasing the velocity, the 'threshold' of turbulent suspen- sion of particles is reached. An increase in the amount of suspended particles with increasing velocity, beyond the sus- pension threshold, leads to the successive decrease in friction losses due to the solids. The relative influence of suspended and non-suspended portions varies and there is no distinct point at which the flow changes to fully-stratified or fully- suspended flow. Partially-stratified flow conditions generally correspond to transportation of sand with mean sizes of about 0.2-2 ram, at velocities of industrial interest in 0.1-0.5 m i.d. pipelines. Products with rather narrow particle size distribu
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