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Non-Return Valve Fluid Flow Tutorial

This article provides a step-by-step tutorial for a fluid dynamic simulation of a non-return valve.

non return valve illustration of a fluid flowing
Figure 1: Particle traces through a non-return valve.


Valves under particular flow conditions can be simulated to obtain key performance quantities such as pressure drop through the system. Additionally, velocity and pressure results can be inspected in detail to identify regions of extreme pressure and flow inefficiencies. This tutorial acts as a guide for valve analysis best practices and can be used as a template for your future projects.

We are following the typical SimScale workflow:

  1. Preparing the CAD model for the simulation.
  2. Setting up the simulation.
  3. Creating the mesh.
  4. Run the simulation and analyze the results.

1. Preparing the CAD Model and Select the Analysis Type

First of all, click the button below. It will copy the tutorial project containing the geometry into your own workbench.

The following picture demonstrates what should be visible after importing the tutorial project.

workbench with non return valve simulation
Figure 2: Imported CAD model of an non-return valve in the SimScale workbench.

You will notice that we are only modelling one half of the valve geometry. Due to having utilized the fact that the valve is symmetrical and this is a great way to save on both mesh size and simulation run time.

1.1 Create an Open Inner Region

Before we can begin a simulation, notice that we must first create the fluid volume. This has been done on the project you have imported from the link above. It is obtained by performing a geometry operation called Open inner region.

open inner region setup
Figure 3: Open inner region setup options.

For the operation:

  • Select the surfaces surrounding the inlet and outlet openings as boundary faces.
  • Select any internal face as the seed face.
open inner region setup
Figure 4: Open inner region setup options.

Once the operation is complete you will be left with the internal fluid volume.

1.2 Create a Simulation

new simulation option
Figure 5: Creating a new simulation.

Hitting the ‘Create Simulation’ button leads to the following options:

simulation menu
Figure 6: SimScale simulation library.

In this simulation we calculate the flow of water through a valve. As long as the speed of the fluid is subsonic (Mach Number below 0.3), we selected the incompressible analysis and ‘create the simulation’.

2. Assign Materials and Boundary Conditions

In order to have an overview, the following picture shows the boundary conditions applied for this simulation:

non return valve boundary conditions
Figure 7: Overview of the boundary conditions for the non-return valve.

2.1 Define a Material

simscale material options
Figure 8: Material library.

To apply the material to the geometry, press the ‘+ button‘ and the menu showed above list the available materials. For this simulation, we will select ‘water‘ and press ‘Apply‘ to confirm the material.

2.2 Assign Boundary Conditions

In the next step, boundary conditions need to be assigned, for this setup, flow, and geometric boundary conditions are required.

a. Flow Conditions

Starting whit the flow conditions, one needs to create a pressure inlet condition to the inlet as shown below.

pressure inlet setup
Figure 9: Boundary conditions.

After hitting the ‘+ button’ next to boundary conditions there will pop up a drop-down menu where one can choose between different boundary conditions.

pressure inlet boundary condition
Figure 10: Assign the first boundary condition.

Assign a pressure outlet condition of mean value 0 gauge pressure to the outlet. This sets the outlet to atmospheric pressure allowing flow to exit freely.

pressure outlet boundary condition
Figure 11: Assign the pressure outlet condition.

b. Geometry Conditions

Assign symmetry conditions to all the surfaces that lie directly on the plane of symmetry.

symmetry boundary condition
Figure 12: Assign the symmetry condition.

Don’t worry about the simulation control settings, since their default values are optimized according to the chosen analysis type, hence valid for the majority of simulations. If you are a simulation expert however, you can have a look at them and change the settings as you like.

You can use result control to observe the convergence behavior of certain items of interest. In this simulation it is not required.

3. Mesh

To get the mesh, we recommend using the standard algorithm, which is a good choice in general because it is quite automated and delivers good results for the most geometries.

mesh menu in simscale
Figure 13: Standard meshing menu.

Did you know?

Often, large changes in the mesh’s cell sizes are only spotted in a few regions. Increasing the global mesh refinements rises the cells drastically.
When using the standard mesher, SimScale offers the option of physics based meshing. This algorithm detects regions which require a finer resolution based on the boundary conditions set.
You can also do this manually, by using one of the local refinement options, foremost being feature, surface and region refinements.

The resulting mesh will have about 226.6k nodes and look like this:

mesh visualization
Figure 14: Mesh result.

4. Start the Simulation

simulation tree in simscale
Figure 15: Simulation setup tree before starting the simulation.

Now you can ‘start’ the simulation, and after about 25 minutes you can have a look at the results.

5. Post-Processing

Once your simulation is complete you can use the online post-processor to visualize the results. To get to grips with the post-processor please refer to the following documentation.

When analyzing valves, it is interesting to examine the velocity behavior through the system. Below shows velocity results with vectors included.

simulation result with cutting plane view
Figure 16: Velocity observed with a cutting plane.

Analyze your results with the SimScale post-processor. Have a look at our post-processing guide to learn how to use the post-processor.

Congratulations! You finished the tutorial!


If you have questions or suggestions, please reach out either via the forum or contact us directly.

Last updated: July 13th, 2020

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