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Relief Valve Analysis with 6DoF Motion – Simulation Template

relief valve
The SimScale Public Project Library contains 200 projects which can be used as templates for your own simulations. There are several valve analyses created to help improve products faster and more efficiently. The most recent project is this analysis, which simulates the opening of a pressure relief valve using 6 DoF body motion.

CFD Simulation of a Relief Valve

This project simulates the opening of a relief valve by fluid pressure via transient analysis with 6 DoF (degree of freedom) motion for the valve. The valve motion was restrained by adding a spring model that was initially in a slightly compressed state. Turbulence modelling was done with the k-omega SST model.

The source geometry included a complete relief valve and was simplified for this internal flow analysis, as shown in the figure below with the valve highlighted in red.

Pressure relief valve CAD model on SimScale

Geometry by GrabCAD user Johann Oberhumer

The complete internal flow domain was meshed using the ‘Snappy-Hex-Mesh’ on the SimScale platform. The resulting mesh (flow domain only) consists of approximately 0.4 million cells and is shown in the figure below.

Pressure relief valve mesh with SimScale

The fluid was taken as water at standard conditions. A fixed inlet velocity of 8m/s was taken with a reference pressure of value 0 at the outlet. The restraining spring had a rest length of 0.41 m and a stiffness coefficient of 20000 N/m. Based on the construction and symmetry condition, constraints were applied for the rotations and lateral motions. The job was run on 4 core computers and took around 16 hours to complete.

The simulation investigates the instantaneous flow field through the valve and the motion due to fluid pressure and spring restraint.

The results below (processed on ParaView) show the transient changes in pressure and flow velocities and the motion of the valve based on the fluid forces. This study shows potential to improve and optimize the valve design and study the real time valve motion.

The figures also show how the pressure distribution changes and a 3D visualization of the streamlines. Shown below is the velocity field at 2 different time instances.

Pressure relief valve simulation with SimScale - velocity

Valve simulation with SimScale

The next result of this valve analysis is the pressure field at two different time instances with arrows indicating the flow direction.

Valve analysis with SimScale

Valve analysis with SimScale platform

Thirdly, the 3D velocity streamlines in the volume at two-time instances are shown below:

Velocity streamlines - valve simulation with SimScale

Valve simulation SimScale

In the plot below, the displacement of the valve over time can be investigated:

displacement of the valve - simulation with SimScale

SimScale offers a cloud-based, powerful, simulation platform that is not only easy to access from anywhere via your browser but also provides all the functionalities needed for 3D simulation, at a fraction of the market price (up to 15x lower than other simulation software providers). Start a 14-day trial and use this valve simulation project as a template for your first simulation.


1. The geometry for this project is courtesy of GrabCAD user Johann Oberhumer.

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