TwinMesh

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Revision as of 09:23, 4 February 2019

TwinMesh

TwinMesh is a meshing software developed by CFX Berlin Software GmbH, Germany. It automatically generates hexahedral meshes for the computational fluid dynamics (CFD) simulation of the continuously changing fluid volumes of the working chambers of rotary positive displacement (PD) machines. The product was released in 2014.

TwinMesh supports floating licenses via LM-X license manager for 64-bit Windows and Linux systems.

The current product release is Version 2019, released in January 2019.

Mesh Types

TwinMesh can generate structured hexahedral meshes for the axial gaps and working chambers of rotary positive displacement machines.
Additionally, TwinMesh can generate unstructured tetrahedral meshes for the axial gaps of rotary positive displacement machines.

Meshing Techniques

TwinMesh's mesh generation employs the following meshing techniques and smoothing algorithms.

• Option to fix the nodes along the rotors, which results in a general interface between the rotor meshes.
• Option to fix the nodes along the housing geometry to get an 1:1 interface between the rotor meshes.
• Option to fix the nodes on one of the rotors so that the nodes on the other rotor are able to move. This method also results in an 1:1 rotor interface.
• Option to mesh rotors with variable pitch.
• Manual adjustment of individual nodes.
• Node mapping at general grid interfaces.
• Various smoothing algorithms to control mesh orthogonality and node equidistance in all three dimensions.
• Mesh quality check such as: determinant, min. angle, volume change, and aspect ratio.

• TwinMesh supports parallel computing with the usage of up to 16 local cores for the meshing process.

Additional Features

• CHT-GGI interface that allows to create a fluid-fluid-solid interface.
• Non-reflecting boundary condition in CFX-Pre.
• Mesh interpolation feature that allows to vary the solver timestep and the rotational speed of the PD machine.
• Consideration of shaft deflection and thermal deformation.

Geometry Support

TwinMesh supports IGES (.iges) and point data (.csv).

The following geometry modifications are available in TwinMesh:

• Rotor scaling
• Rotor translation
• Rotation angle offset

Rotary Positive Displacement Machines

TwinMesh allows meshing of the following rotary PD machines:

• Internal/external gear pump
• Gerotor pump
• Orbital motor
• Vane pump
• Lobe pump
• Roots blower
• Rotary piston pump
• Scroll compressor/expander
• Conical rotor pump
• Screw compressor/expander
• Eccentric screw pump/progressive cavity pump
• Wankel engine

CFD Solver Interfaces

TwinMesh has built-in support for ANSYS CFX and automatically generates ready-to-run templates for ANSYS CFX and ANSYS CFD PrepPost.

Supported Platforms

TwinMesh supports 64-bit Windows versions.

Literature

• Hesse, J., Spille-Kohoff, A., Hauser, J., & Schulze-Beckinghausen, P. (2014). Structured meshes and reliable CFD simulations: TwinMesh for positive displacement machines. In International screw compressor conference, TU Dortmund.
• Spille-Kohoff, A., Hesse, J., & El Shorbagy, A. (2015, August). CFD simulation of a screw compressor including leakage flows and rotor heating. In IOP Conference Series: Materials Science and Engineering (Vol. 90, No. 1, p. 012009). IOP Publishing. ([1])
• Andres, R., Nikolov, A., & Brümmer, A. (2016). CFD Simulation of a Twin Screw Expander including Leakage Flows. In 23rd International Compressor Engineering Conference at Purdue, July 11-14, 2016. ([2])
• Willie, J. (2017, September). Use of CFD to predict trapped gas excitation as source of vibration and noise in screw compressors. In IOP Conference Series: Materials Science and Engineering (Vol. 232, p. 012021). IOP Publishing. ([3])
• Pietrzyk, P., Roth, D., Schmitz, K. & Jacobs, G. (2018). Design study of a high speed power unit for electro hydraulic actuators (EHA) in mobile applications. In 11th International Fluid Power Conference Aachen, March 19-21, 2018. ([4])

External Links

* TwinMesh's homepage
* CFX Berlin's homepage