Nigel Heywood - Academia.edu (original) (raw)
Papers by Nigel Heywood
This paper provides a summary of slurry tank design for feeding and receiving slurry transported ... more This paper provides a summary of slurry tank design for feeding and receiving slurry transported through pipelines. It considers the solids suspension mechanisms, the relevant physical properties of the solid and liquid phases, and the type, number and position of appropriate agitators. Slurry tank operation covers the degree of solid suspension required such as "just-suspension" and cloud height, including the prediction of "just-suspension" agitator speed. The effect of the partial discharge and complete draining of a slurry tank, and therefore a progressive decrease in the slurry level in the tank, on the extent of particle suspension is also covered.
The frictional pressure gradient for the horizontal, laminar pipe flow of non-Newtonian slurries ... more The frictional pressure gradient for the horizontal, laminar pipe flow of non-Newtonian slurries can be very large. Injecting gas into the pipe immediately downstream from a p ump can reduce the friction by 80% or more and occurs for the stratified, elongated bubble and slug flow patterns only. No reduction in pressure loss occurs when the flow is in the turbulent regime for either Newtonian or non-Newtonian fluids, nor is there any for a Newtonian fluid flowing in the laminar regime. As well as a reduction in frictional pressure loss, there is sometimes also an overall power saving (i.e., power to compress the gas is less than the reduction in pump power arising from gas injection), depending on the relative compressor and pump efficiencies. There is an optimal gas flowrate which achieves the greatest reduction in frictional pressure loss and this depends on several factors including the slurry flow curve, slurry flowrate, internal pipe diameter and therefore pipe Reynolds number f...
Chemical Engineering Progress
This paper provides a summary of slurry tank design for feeding and receiving slurry transported ... more This paper provides a summary of slurry tank design for feeding and receiving slurry transported through pipelines. It considers the solids suspension mechanisms, the relevant physical properties of the solid and liquid phases, and the type, number and position of appropriate agitators. Slurry tank operation covers the degree of solid suspension required such as "just-suspension" and cloud height, including the prediction of "just-suspension" agitator speed. The effect of the partial discharge and complete draining of a slurry tank, and therefore a progressive decrease in the slurry level in the tank, on the extent of particle suspension is also covered.
The frictional pressure gradient for the horizontal, laminar pipe flow of non-Newtonian slurries ... more The frictional pressure gradient for the horizontal, laminar pipe flow of non-Newtonian slurries can be very large. Injecting gas into the pipe immediately downstream from a p ump can reduce the friction by 80% or more and occurs for the stratified, elongated bubble and slug flow patterns only. No reduction in pressure loss occurs when the flow is in the turbulent regime for either Newtonian or non-Newtonian fluids, nor is there any for a Newtonian fluid flowing in the laminar regime. As well as a reduction in frictional pressure loss, there is sometimes also an overall power saving (i.e., power to compress the gas is less than the reduction in pump power arising from gas injection), depending on the relative compressor and pump efficiencies. There is an optimal gas flowrate which achieves the greatest reduction in frictional pressure loss and this depends on several factors including the slurry flow curve, slurry flowrate, internal pipe diameter and therefore pipe Reynolds number f...
Chemical Engineering Progress