The main purpose of this tutorial is to learn to set up and process a Liquid Bridge simulation for later mixing analysis.

The scenario considered in this tutorial is evaluating the mixing performance of a Ribbon Blender combining two different materials: one powder material (dry) and one additive material (wet).

You will learn how to:

And you will use these features:

To make use of the referenced external module, you must have Rocky 2025 R2 or later and your version of Rocky must be the same as the SDK version in which the module was compiled.

For this tutorial, an external module will be installed and used.

External modules are not installed with the Rocky product by default; rather, they are downloaded and installed separately.

To install the module, do the following:

The geometries in this tutorial are composed of:

These two items will be imported as .stl files, which can be found in the tutorial directory.

To get started setting up this tutorial, do the following:

For the Modules step, we will be enabling the Liquid Bridge Model module.

First, let's turn on the Liquid Bridge Model module:

To see the parameters you are able to set:

In addition to those listed in the module itself, additional Liquid Bridge parameters will be available in other locations of the Rocky setup, including:

Now that the module is enabled, we can begin setting up other parts of the project.

Earlier in the Modules step, we enabled the Liquid Bridge Model module.

Doing so turned on additional parameters in other parts of the Rocky UI, including for Materials Interactions.

The additional Liquid Bridge Model parameters that you can set for your Materials Interactions pairs are as follows:

For this tutorial, we will create one Volumetric Inlet with Dry powder particles and a Particle Inlet with Wet additive particles.

In this way, we will have two distinct layers of particles to better analyze the mixing:

Earlier in the Modules step, we enabled the Liquid Bridge Model module, which turned on additional parameters in other parts of the Rocky UI, including for Inlets and Outlets.

This additional parameter appears on a new Modules sub-tab for your Inputs:

Now, we'll create a Volumetric Inlet that injects the Dry Powder particles, and will finish setting up the rest of our project.

With a 3D View window opened, your Data panel and Workspace should look similar to the below image.

The Simulation Summary screen appears (as shown), then processing begins.

This completes Part A of this tutorial, in which Rocky was used to set up and process a Ribbon Blender simulation.

During this tutorial, it was possible to:

What's Next? If you completed this tutorial successfully, then you are ready to move on to Part B and/or Part C and post-process this project.

The main purpose of this tutorial is to use the results of the simulation we set up and processed in Part A to analyze the mixing efficiency using the Lacey Mixing Index (LMI).

As a reminder, the scenario considered in this tutorial is a Ribbon Blender mixing two different materials: one (dry) powder material and one (wet) additive material.

You will calculate the LMI by learning how to:

And you will use these features:

To make use of the external module referenced, you must have Rocky 2025 R2 or later and your version of Rocky must be the same as the SDK version in which the module was compiled.

If you completed Part A of this tutorial, ensure that Rocky project is open. (Part B will continue from where Part A left off.)

If you did not complete Part A, do all of the following:

With the processing complete, we can now start analyzing our results.

At any given time, Properties can be used to color the Particles in a 3D View window.

For example, you can do the following:

In order to evaluate the uniformity of mixing, we will divide the mixture into samples and will measure the Mass Fraction of Additive Particles in each sample.

A good degree of mixing means that the mass fractions of the samples are approximately the same.

Each discrete volume (cell) will represent a different sample of our mixture.

To compare the degree of uniformity between samples, we can calculate their Additive Mass Fraction Variance.

The higher the variance, the more heterogeneous is the system, which means a poor degree of mixing.

The Lacey Mixing Index (LMI) is often used to evaluate the uniformity of mixing. It can be interpreted as a normalization of the mass fraction variance, and will provide values ranging from 0 to 1.

The Lacey Mixing Index can be defined as:

(18–1)

The equation components are described below.

Where:

Particles Properties and Tagging Calculations will be used to filter the Wet Additive Particles.

Tagging allows you to define a Global value to particles that meet a specific criterion in a particular Output Time.

To select a group of particles, we will create a new Filter User Process that filters particles based on their properties.

In this tutorial, we will Tag the Wet Additive Particles with a value of 1, which will automatically make all other untagged particle groups have a value of 0.

This separation will be needed later when we calculate the mass of the Wet Additive particles only.

Next, we will define a new property that multiplies the Tag value and the Particles Mass value, which we will call Mass If Additive.

In this way, if the particle is a Wet Additive particle, the value of this new custom property is the Particle Mass. Otherwise, the value will be zero.

A new property called Mass If Additive (Custom) appears on the Properties tab for Particles.

Now that we've defined the Mass If Additive property, we need to divide the Ribbon Blender tank into samples.

For this step, we will create a Cylinder User Process and then apply Eulerian Statistics divisions to the cylinder.

The Additive Mass Fraction will then be calculated for each individual cell by adding a new expression defined as the Additive Mass divided by the Particle Mass.

Next, we will calculate the Additive Mass Fraction in each cell.

First we need to calculate both the sum of all particles mass and the Wet Additive particle mass in each cell.

From the Properties tab of the Eulerian Statistics <01> entity, the two new custom properties appear.

The last step to visualize the mass fraction is to divide the Sum of Mass If Additive (Custom) by the Sum of Particle Mass using a new Custom Property.

The newly created property will be available on the Properties tab for the Eulerian Statistics <01> entity.

In order to evaluate the Lacey Mixing Index (LMI) unbiased, we'll select and analyze only those cells with the highest amounts of particles, to ensure better representative samples.

For this step, we will filter the cells based on their mass.

This completes Part B of this tutorial, in which Rocky was used to calculate the Lacey Mixing Index (LMI) of the Ribbon Blender simulation we set up and processed in Part A.

During this tutorial, it was possible to:

What's Next? If you completed this tutorial successfully, then you are ready to move on to Part C and continue post-processing this tutorial.

The main purpose of this tutorial is to use the results of the liquid bridge simulation we set up and processed in Part A to analyze the distribution of liquid during mixing.

As a reminder, the scenario considered in this tutorial is a Ribbon Blender mixing two different materials: one (dry) powder material and one (wet) additive material.

You will learn how to:

And you will use these features:

To make use of the external module referenced, you must have Rocky 2025 R2 or later and your version of Rocky must be the same as the SDK version in which the module was compiled.

If you completed Part A (and/or ) of this tutorial, ensure that Rocky project is open. (Part C will continue from where Part A (or Part B) left off.)

If you did not complete Part A (and/or Part B), do all of the following:

With the processing complete, we can now start analyzing our results.

Earlier in Part A we enabled the Liquid Bridge adhesion model, which performs the following functions during processing:

After processing the simulation, a new property is available for Particles:

We can use this new property to see how the dry particles were affected by the wet particles during mixing.

The Liquid Mass of the particles is shown.

To change the color scale, do the following:

Use the slider on the Time toolbar to see how the liquid from the Wet Additive (blue) is transferred to the Dry Powder (white) over time.

We can also plot the average Liquid Mass of both the dry and wet particles on a Time Plot.

But first, we need to separate the groups by creating two Filter User Processes.

The resulting Time Plot shows that by the end of the simulation, the liquid that was initially only in the wet particles is after mixing, evenly distributed throughout both the wet and dry particles.

Now let's analyze the liquid dispersion, starting from the beginning of the simulation.

The resulting Histogram (at 1 s) shows that at the very beginning of the simulation, 100% of the liquid is concentrated on the wet additive.

You can explore how the liquid spreads over time by moving the Time slider forward.

For example, a few seconds into the simulation, fewer particles remain completely dry than at the beginning of the simulation. (Results shown at 3 s.)

By the end of the simulation, the liquid content is gathering around the average. (Results shown at 10 s.)

This completes Part C of this tutorial, in which Rocky was used to analyze the liquid distribution within the Ribbon Blender simulation we set up and processed in Part A.

During this tutorial, it was possible to:

What's Next? If you completed this tutorial successfully, then you are ready to move on to next tutorial.