This method took advantage of the work done by Peric and Demirdzic, who showed that by the use of moving frames on structured and unstructured grids, a common numerical method could be used for the simultaneous solution of fluid flow and structural analysis. A number of commercial numerical solvers are currently available, of which SCORG employs Star CD’s COMET for screw machine calculations. That code offers the possibility to calculate both the fluid flow and its effects on the solid structure simultaneously by the application of CCM.

The interface employs a novel procedure to discretise rotor profiles and to adapt boundary points for each particular application. An analytical transfinite interpolation method with adaptive meshing is used to obtain a fully structured 3-D numerical mesh, which is directly transferable to a CFD code. This is required to overcome problems associated with moving, stretching and sliding rotor domains and to allow robust calculations in domains with significantly different ranges of geometry features. 

SCORG prepares a numerical mesh of the domains in the vicinity of the rotors for 3-D flow and structure analysis. This is done by integrating the data of rotor and rack profiles from the SCORPATH input. At the same time, SCOCCM uses the integration of CAD and CCM software to generate polyhedral numerical meshes of the stationary parts of the numerical mesh. It then integrates the compressor geometry and working parameters generated by the SCORG and CAD systems with the commercial CCM, software. The computational grid of the screw compressor rotors generated by SCORG and the numerical grid of other parts of the compressor, including the suction or the discharge chambers, which may be generated from either the SCORG or the CAD system, are imported into the CCM software through the pre-processor script file. That file also contains working parameters, information of the differencing scheme and other required solver information. Finally, the results obtained from the CCM calculations are evaluated so that the design of the machine can be reviewed and changed if required.