In this simulation I applied the simplest multiphase solver available in OpenFOAM to simulate a flow through a classical Venturi meter with mercury as the manometer fluid. In this project I created my on CAD geometry of a standardized venturi meter and compared the simulation results with calculations based on the well known equations regarding the Venturi meter.
The geometry I used for the Venturi flow meter comes from this papar. You can see a drawing of the part I used in the Geometry and Mesh part.
Note: The throat pressure tappings are larger than prescribed in the ISO 5167-4:2003 standard. Despite this, the results are fairly accurate, but the geometry should be changed in order to make the simulations more akin to real-world use.
Using the Bernulli equation, the continuity equation, and the hydrostatic pressure equation, it is trivial to arrive at the following equation for the mercury level height diference h:
The expected value of h is 1.5 cm.
I made the geometry and a drawing with SolidWorks (the files are available in the geometry folder), then saved them in the STL format and imported it into Blender where I extracted and named the patches in order to prepare them for meshing with snappyHexMesh.
After that I made a relatively simple mesh with snappyHexMesh (all parameters can be seen in the snappyHexMeshDict located in the system folder).
For this simulation I used interFoam, which is a transient, incompressible, turbulent, immisible, isothermal, VOF solver.
For the turbulence model I used the K Omega SST model and initialized the their values using these recommendations.
After reaching a steady level, the observed height difference is around 1.46 cm.
This is very close to the expected value, but still, simulations with different parameters should be added in the future for more validation.