Development of a Computational Fluid Dynamics Model for a High-Speed Centrifugal Compressor

Computational fluid dynamics (CFD) has become widely used in the design and analysis
of turbomachinery components such as centrifugal compressors. However, CFD is only a limited
representation of experimental cases and struggles to model complex flows or can lack small
model details to increase computation speed. To make advancements in compressor technology,
designers need tools like CFD that can help them predict flow behavior in new designs. The
High Efficiency Centrifugal Compressor (HECC) was designed by United Technologies
Research Center (UTRC) for NASA to investigate the difficulties behind improving centrifugal
compressor technology and to provide an open case to the turbomachinery research community.
CFD analysis was completed by UTRC to aid in the design process. The pre-test study
significantly overpredicted the compressor’s performance, and while post-test analysis was more
representative, its results have yet to be publicly available. CFD technology has also since
improved in recent years. In this study, a high-fidelity computational model for the vaneless
configuration of HECC operating at its design point was developed and compared to an
equivalent experimental case. This model incorporated GPU versions of mesh generation and
solver codes from AeroDynamic Solutions, Inc. The development of such a model is significant
since there has yet to be a published numerical simulation of HECC’s vaneless configuration.
Additionally, the use of GPU codes decreases computation times for the model, which has
allowed for the inclusion of impeller blade fillets. Initial results showed a general overprediction of compressor performance by the model. Predictions were more accurate for the impeller
compared to predictions for the full compressor stage. Spanwise analyses showed that the model
tended to follow flow behavior patterns exhibited in the experiment. Beyond this study, this
model will be iterated upon and experimentally validated to further examine HECC performance.