In the final stage of the design process, screw compressor performance may be estimated more precisely by use of Three-dimensional Computational Fluid Dynamics (CFD) or Computational Continuum Mechanics (CCM). Please search Compressor Centre Bibliography. The aim of 3-D numerical simulation is not to reconfirm 1-D calculation of thermodynamics but rather to serve as an optimisation tool for the suction and discharge ports as well as to provide the flow information needed for flow-structure analysis. The same numerical grid is simultaneously used for estimation of distortions of the compressor elements and its influence to the flow parameters.

A number of commercial CFD software packages are currently available which may be able to cope with the complexity of flow through screw machines and which may be integrated with CAD. However, the authors most commonly employ COMET of Star CD for screw machine calculations, firstly, because that code enables  both fluid flow and its interaction with the solid structure to be calculated simultaneously by use of the Computational Continuum Mechanics (CCM) principle already incorporated in the code. Secondly, because the code, as a CAE package, is already integrated in some CAD systems.  This made the development of the integration software easier. Thirdly, it uses a modern polyhedral topology of computational control volumes to map the geometry. Polyhedral cells allow both easier grid generation and more accurate solution in a mesh with a lower number of cells. This improves the computational speed.

However developed new codes are, there are still limitations of their use in some specific application. For the analysis of screw machines, a moving, stretching and sliding mesh has to be produced to map the working chamber of a machine. Today’s grid generators are still not capable of coping with these demands.

Articles about SCOCCM:
    - STAR-CD: "CFD and stress analysis in screw compressor design"