In this animation, a progressive cavity pump (eccentric screw pump; in german: "Exzenterschneckenpumpe") with a 2/3 ratio lobe geometry is shown where the helical rotor has an ellipsoidal cross section.
The CFD simulation has been setup with TwinMesh™ and ANSYS™ CFX. The rotor has a wrap angle of 720° with a length of 360 mm. The ellipsoidal cross section has a major axis of 72 mm and a minor axis of 40 mm. The stator is assumed rigid (not an elastomer) with a gap size of 0.1 mm between rotor and stator. The fluid region between the rotor and the stator was meshed with TwinMesh™ with 180 elements in circumferential, 25 in radial and 200 in axial direction. 90 meshes for a rotational increment of 2° were pre-generated (and read at run-time by the CFD solver to define mesh deformation). Inlet and outlet regions were created as simple cylinders with 120,000 hexahedrons for pressure and suction side.
Simulation was done with ANSYS™ CFX for water with dynamic viscosity of 0.89 mPa s and at 200 rpm rotational speed; suction side is at 1 bar, pressure side at 2 bar absolute. In the beginning, a tracer (like ink in water) is assumed homogeneous in the suction side cylinder. The animation shows the transport of the tracer towards the pressure side as volume rendering, colored by absolute pressure. Each time step corresponds to 2° rotation of the rotor. After 180 time steps, i.e. 360° rotation, the rotor is fully filled with the tracer.
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