15th European Conference on Turbomachinery Fluid dynamics & Thermodynamics
Authors
Abstract
This work focuses on centrifugal compressors utilised in hydrogen pipeline systems. As outlined in previous studies, the demand for Mach-number similarity and reduced number of compressor stages requires an increase of the tip-speed up to 1200 m/s. At this tip-speed, the mechanical stresses occurring in conventional impeller designs exceed the material limits. This work aims to reduce the peak mechanical stress in the impeller by changing the impeller shape. A generic optimisation algorithm is utilised to find an impeller design that reduces the mechanical stress significantly but only penalises the polytropic efficiency slightly. This work starts with a standard impeller design, operated with air in the closed-loop test stand at LUT. A parameterised model of the impeller is established. This model is input to an optimisation algorithm. This optimisation algorithm predicts aerodynamic performance with three-dimensional computational fluid dynamics (CFD) and mechanical stress with the finite element method (FEM). In addition, Fluid-Structure Interaction (FSI) simulations of the impellers are conducted and optimal designs are studied. By design of experiments (DoE) first candidates are generated and analysed. The results are used as a first generation for the optimisation algorithm. Convergence of the optimisation is monitored and final results are displayed as a Pareto front. The most promising candidates are analysed in detail regarding structural mechanic and fluid dynamic aspects. Aspects leading to a reduction of mechanical stresses are extracted and can be used in future designs.
ETC2023-109