## Turbulent deposition

What is turbulent deposition?

Turbulent deposition in a slurry refers to the process by which solid particles in a slurry are separated from the fluid and deposited on the walls of a pipe or other container. This can occur when the fluid flow becomes turbulent, causing the solid particles to lose their momentum and settle out of the flow.

Turbulent deposition can be influenced by several factors, including the size, shape, and density of the particles, the velocity and turbulence of the fluid flow, and the roughness of the pipe or container walls.

This phenomenon can cause a number of problems, including reduced flow capacity, increased pressure drop, and erosion of the pipe walls. In some cases, it can also lead to blockages and damage to equipment downstream.

To minimize the effects of turbulent deposition, measures can be taken such as using larger pipe diameters, increasing the fluid velocity, or using a more abrasive-resistant pipe material. Additionally, using a slurry pump with a higher head can help to mitigate the effects of turbulent deposition.

It's also important to note that turbulent deposition can also be caused by insufficient mixing and segregation of the particles, and adequate mixing and agitation can help to prevent this from occurring.

How do you calculate turbulent deposition?

Calculating turbulent deposition in a slurry can be complex and is highly dependent on the specific properties of the fluid and particles, as well as the conditions of the flow.

There are several empirical models that have been developed to predict turbulent deposition in slurry pipelines, such as the Ergun equation, the Wen-Yu equation, and the Rumpf equation. These models typically require information on the properties of the slurry, such as the particle size and density distribution, as well as the fluid velocity and pipe diameter.

The Ergun equation is one of the most widely used models for predicting turbulent deposition in slurry pipelines. It is a modified form of the Darcy-Weisbach equation and takes into account the effects of particle size, density, and concentration on the pressure drop and friction factor.

The Wen-Yu equation is another model that can be used to predict turbulent deposition in slurry pipelines. It is based on the Ergun equation and includes a correction factor for particle-size distribution and concentration.

The Rumpf equation is another widely used model, it is based on the Ergun equation and includes a correction factor for particle shape.

The choice of model to use depends on the properties of the slurry and the type of flow. Additionally, these models are based on assumptions and empirical data, and their validity is limited to certain ranges of the parameters, thus, it is important to validate the results against experimental data.

It's worth noting that the accuracy of these models is highly dependent on the quality of the data and the conditions used to obtain it. Therefore, it's important to measure or estimate the properties of the slurry, such as particle size and density, and the conditions of the flow, such as velocity and pipe diameter, at the time of the experiment or design.