• CFD
• Labyrinth Seals
• Coefficient Rotordynamic

ABSTRACT

The subject analyzed in this thesis developed for the Master degree in Mechanical Engineering, rotordynamic field, was about the investigation of rotordynamic coefficients of labyrinth seals installe on turbomachinery (centrifugal compressor) by the use of the numerical CFD code -CFX.
The work has been subdivided in three phases: the first phase treated the research of the right settings of CFX code when applied to a simplified labyrinth seal geometry, in unsteady field with mesh movement; the second phase focused on the use of two techniques to extract from CFD code the forces between the seal and the rotor. These techniques were applied both to a simplified seal and to a real geometry labyrinth seal (this was also tested on rotordynamic test rig internally in GE). The third phase was about the identification of the rotordynamics coefficients based on the previously extracted forces. This was done using three different methods.
The data got from the CFX were compared with the results from a Bulk-Flow code with one control volume and, (at least for the real geometry seal), with the experimental results extracted by the test rig.
From these comparisons a qualitative mach between coefficients extracted by CFX and experimental results is shown.
The CFD application to the labyrinth seals rotordynamic coefficients used in the present thesis work showed the need for high computational resources so further research and development is needed to make it effective for the design activity in industrial environment.