<abstract xmlns="http://www.w3.org/1999/xhtml">In slurry transport of settling slurries in Newtonian fluids, it is often stated that one should apply a line speed above a critical velocity, because blow this critical velocity there is the danger of plugging the line. There are many definitions and names for this critical velocity. It is referred to as the velocity where a bed starts sliding or the velocity above which there is no stationary bed or sliding bed. Others use the velocity where the hydraulic gradient is at a minimum, because of the minimum energy consumption. Most models from literature are one term one equation models, based on the idea that the critical velocity can be explained that way.Here the following definition is used: The critical velocity is the line speed below which there may be either a stationary bed or a sliding bed, depending on the particle diameter and the pipe diameter, but above which no bed (stationary or sliding) exists, the Limit Deposit Velocity (LDV). The way of determining the LDV depends on the particle size, where 5 regions are distinguished.These regions for sand and gravel are roughly; very small particles up to 0.014–0.040 mm (<italic>d</italic> &lt; <italic>δv</italic>), small particles from δ<italic>v</italic>–0.2 mm, medium particles in a transition region from 0.2–2.00 mm, large particles > 2 mm and very large particles > 0.015·<italic>Dp</italic>. The lower limit of the LDV is the transition between a sliding bed and heterogeneous transport. The new model is partly based on physics and correlates well with experiments from literature.</abstract>

In slurry transport of settling slurries in Newtonian fluids, it is often stated that one should apply a line speed above a critical velocity, because blow this critical velocity there is the danger of plugging the line. There are many definitions and names for this critical velocity. It is referred to as the velocity where a bed starts sliding or the velocity above which there is no stationary bed or sliding bed. Others use the velocity where the hydraulic gradient is at a minimum, because of the minimum energy consumption. Most models from literature are one term one equation models, based on the idea that the critical velocity can be explained that way.Here the following definition is used: The critical velocity is the line speed below which there may be either a stationary bed or a sliding bed, depending on the particle diameter and the pipe diameter, but above which no bed (stationary or sliding) exists, the Limit Deposit Velocity (LDV). The way of determining the LDV depends on the particle size, where 5 regions are distinguished.These regions for sand and gravel are roughly; very small particles up to 0.014–0.040 mm (d < δv), small particles from δv–0.2 mm, medium particles in a transition region from 0.2–2.00 mm, large particles > 2 mm and very large particles > 0.015·Dp. The lower limit of the LDV is the transition between a sliding bed and heterogeneous transport. The new model is partly based on physics and correlates well with experiments from literature.

The Limit Deposit Velocity model, a new approach

Delft University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands.

Manager Production Department, Great Lakes Dredge & Dock, 2122 York Road, Oak Brook, IL 60523 USA.

Journal of Hydrology and Hydromechanics

This chapter is distributed under the terms of the Creative Commons Attribution 4.0 Public License.

{"article-title":"The Limit Deposit Velocity model, a new approach"}

In slurry transport of settling slurries in Newtonian fluids, it is often stated that one should apply a line speed above a critical velocity, because blow this critical velocity there is the danger of plugging the line. There are many definitions and names for this critical velocity. It is referred to as the velocity where a bed starts sliding or the velocity above which there is no stationary bed or sliding bed. Others use the velocity where the hydraulic gradient is at a minimum, because of the minimum energy consumption. Most models from literature are one term one equation models, based on the idea that the critical velocity can be explained that way.Here the following definition is used: The critical velocity is the line speed below which there may be either a stationary bed or a sliding bed, depending on the particle diameter and the pipe diameter, but above which no bed (stationary or sliding) exists, the Limit Deposit Velocity (LDV). The way of determining the LDV depends on the particle size, where 5 regions are distinguished.These regions for sand and gravel are roughly; very small particles up to 0.014–0.040 mm (d  2 mm and very large particles > 0.015·Dp. The lower limit of the LDV is the transition between a sliding bed and heterogeneous transport. The new model is partly based on physics and correlates well with experiments from literature.

In slurry transport of settling slurries in Newtonian fluids, it is often stated that one should apply a line speed above a critical velocity, because blow...

The Limit Deposit Velocity model, a new approach

Pubblicato online: 20 ott 2015

Pagine: 273 - 286

Ricevuto: 11 nov 2014

Accettato: 15 giu 2015

DOI: https://doi.org/10.1515/johh-2015-0034

Parole chiave
Critical velocity, Limit Deposit Velocity, Slurry transport, Newtonian fluid

© 2015 Sape A. Miedema et al., published by De Gruyter Open

This chapter is distributed under the terms of the Creative Commons Attribution 4.0 Public License.

The Limit Deposit Velocity model, a new approach

Pubblicato online: 20 ott 2015

Pagine: 273 - 286

Ricevuto: 11 nov 2014

Accettato: 15 giu 2015

DOI: https://doi.org/10.1515/johh-2015-0034

Parole chiaveCritical velocity, Limit Deposit Velocity, Slurry transport, Newtonian fluid

© 2015 Sape A. Miedema et al., published by De Gruyter Open

This chapter is distributed under the terms of the Creative Commons Attribution 4.0 Public License.

Parole chiave
Critical velocity, Limit Deposit Velocity, Slurry transport, Newtonian fluid