Session: 37-02 Radial Turbomachinery Optimization

Paper Number: 124863

124863 - Experimentally Verified Optimization of a Two-Stage Real Gas Centrifugal Compressor Using an Industrial-Ready Adjoint Method 

The ongoing climate challenges have lead to a series of governmental regulations
to reduce Ozone Depletion Potential (ODP) and Global Warming Potential (GWP). As man-made synthetic
refrigerants were found to decay towards more harmfull substances, natural gases are considered a promising replacement.

The redesign of corresponding centrifugal compressors is however a challenging task. The
vicinity of the two-phase region requires accurate real gas models and the complexity of the flow
patterns a robust numerical integration of the underlying governing equations.

This article therefore describes the development and application of a fully-coupled,
pressure based CFD framework, incorporating a highly flexible discrete
adjoint method. Due to the stability of the algorithm and the level of achieved
convergence, the gradient based optimization strategy is able to fully
account for real gas and turbulence models during the optimization procedure.

Using a two-stage centrifugal compressor, the return channel
is optimized to achieve an overall reduction in entropy generation. The
resulting geometry is manifactured and an extensive measurement campaign is
carried out. The new compressor map is then compared against the reference
compressor, which was based on standard design criterias.

Although being a single point optimization, the resulting performance characteristics
shows a consistent improvement over the whole characteristic with maximum values of
up to two percent.

Presenting Author: Lucian Hanimann Lucerne University of Applied Sciences and Arts

Presenting Author Biography: Finished the master in mechanical engineering at ETH Zurich with the thesis topic being the implementation of a mixing plane for OpenFOAM. Continued the work at the Lucerne University of Applied Science and Arts to the final fully implicit method, published at ASME in 2013. Further research in the field of CFD lead to a PhD at the University of Stuttgart with the subject being the implementation of a Euler-Euler coupled, pressure-based method for the analysis of steam turbines, finished in 2022. Since the continue the research in the field of numerical methods at the Lucerne University of Applied Science and Arts.

Authors:

Lucian Hanimann Lucerne University of Applied Sciences and Arts
Benno Fleischli Lucerne University of Applied Sciences and Arts
Luca Mangani Lucerne University of Applied Sciences and Arts
Ernesto Casartelli Lucerne University of Applied Sciences and Arts
Ansgar Weickgenannt Teqtoniq GmbH
Andreas Lehr Teqtoniq GmbH