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CFX BerlinVideo Comparison Progressive Cavity Pumps CFD analysis with TwinMesh and CFX
>> YOUR LINK HERE: ___ http://youtube.com/watch?v=0GseolSi_5k
In this animation, three different progressive cavity pumps (eccentric screw pump, Moineau pump; in german: Exzenterschneckenpumpe ) are compared. All are based on hypo-epi-cycloids; the geometry construction is taken from Jens Gravesen, DTU Denmark (http://www2.mat.dtu.dk/people/J.Grave.... • The rolling circle that creates the epi-cycloids or hypo-cycloids has a radius of 10 mm for all three cases; the inner circle for the rotor has a radius of 20 mm, 40 mm, and 60 mm, the outer circle for the stator 40 mm, 60 mm, 80 mm, for the 1:2, 2:3, and 3:4 pump, respectively. The cycloids were conctructed with a Perl script and transferred to TwinMesh™ as csv file. • The CFD simulation has been setup with TwinMesh™ and ANSYS™ CFX. The rotors have a wrap angle of 1440° with a length of 720 mm. The stator is assumed rigid (not an elastomer) with a gap size of 0.1 mm between rotor and stator. The fluid regions between the rotor and the stator were meshed with TwinMesh with 180 elements in circumferential, 25 in radial and 360 in axial direction. 180 (1:2 pump), 90 (2:3 pump), and 60 (3:4 pump) 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 an artificially increased dynamic viscosity of 0.1 Pa s with suction side at 1 bar and pressure side at 2 bar absolute. Rotational speed was adjusted to get similar mass flows: 200 rpm for the 1:2 pump, 80 rpm for the 2:3 pump, and 40 rpm for the 3:4 pump. As a result, average massflow was 4.29 kg/s (1:2 pump), 4.31 kg/s (2:3 pump), and 4.01 kg/s (3:4 pump). Specific power is approx. 110 kWs/m³ for all three cases. • The animation shows absolute pressure on rotor surfaces for the three different pumps for two rotor revolutions (2x 180 time steps). Each time step corresponds to a rotation increment of 2° of the rotor; due to the different rotational speeds, time step size is different in the three cases. The plot at the right bottom compares mass flow rate over rotation angle for all three cases and shows the mostly uniform pumping behaviour of a progressive cavity pump. • Find out more about TwinMesh™: www.twinmesh.com
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