Thermal management for gas lubricated, high-speed turbomachinery

Olmedo, Luis Eric; Liu, W.; Gjika, Kostandin; Schiffmann, Jürg

doi:10.1016/j.applthermaleng.2022.119229

Cited by 5 publications

(2 citation statements)

References 33 publications

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“…However, increasing the stage load affects the compressor aerodynamics through increased diffusion and reduced efficiency, hence posing a conflicting requirement for the designer [2], sometimes demanding the search for optimization methodologies [3]. For high-speed compressors, which usually present difficulties related to the cooling system [4], an increase in diffusion may also result in shock-induced boundary layer separation, drastically lowering efficiency. Still, a highly loaded stage is a possible solution to reduce the number of stages and consequently to decrease compressor weight, size and cost.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Blade Aspect Ratio’s Influence on High-Speed Axial Compressor Performance

Silva,

Grönstedt,

Xisto

et al. 2024

Aerospace

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The ratio between blade height and chord, named the aspect ratio (AR), plays an important role in compressor aerodynamic design. Once selected, it influences stage performance, blade losses and the stage stability margin. The choice of the design AR involves both aerodynamic and mechanical considerations, and an aim is frequently to achieve the desired operating range while maximizing efficiency. For a fixed set of aerodynamic and geometric parameters, there will be an optimal choice of AR that achieves a maximum efficiency. However, for a state-of-the-art aero-engine design, optimality means multi-objective optimality, that is, reaching the highest possible efficiency for a number of operating points while achieving a sufficient stability margin. To this end, the influence of the AR on the performance of the first rotor row of a multistage, multi-objective, high-speed compressor design is analyzed. A careful setup of the high-speed aerodynamic design problem allows the effect of the AR to be isolated. Close to the optimal AR, only a modest efficiency variation is observed, but a considerable change in compressor stability margin (SM) is noted. Decreasing the AR allows for increasing efficiency, but at the expense of a reduced surge margin. This allows the designer to trade efficiency for stability. Increasing the AR, however, is shown to reduce both the surge margin and efficiency; hence, a distinct optimality in stability is observed for the analyzed rotor blade row. In this work, optimality in the surge margin with respect to the AR is observed, whereas there is a close to optimal efficiency. The predicted range from AR = 1.10 to AR = 1.64 is only indicative, considering that the definition of multi-objective optimality requires balancing efficiency and the surge margin and that the choice of balancing these two criteria requires making a design choice along a pareto optimal front.

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Section: Introductionmentioning

confidence: 99%

Analysis of Blade Aspect Ratio’s Influence on High-Speed Axial Compressor Performance

Silva,

Grönstedt,

Xisto

et al. 2024

Aerospace

View full text Add to dashboard Cite

show abstract

“…However, increasing the stage load affects the compressor aerodynamics through increased diffusion and reduced efficiency hence posing a conflicting requirement for the designer [2], sometimes demanding the search for optimization methodologies [3]. For high-speed compressors, which usually present difficulties related to cooling system [4], an increase in diffusion may also result in shock-induced boundary layer separation, drastically lowering efficiency. Still, a highly loaded stage is a possible solution to reduce the number of stages, and consequently to decrease compressor weight, size and cost.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Blade Aspect Ratio Influence on High-Speed Axial Compressor Performance

Silva,

Grönstedt,

Xisto

et al. 2024

Preprint

View full text Add to dashboard Cite

The ratio between blade height and chord, named aspect ratio (AR), plays an important role in compressor aerodynamic design. Once selected, it influences stage performance, blade losses, and the stage stability margin. The choice of the design AR involves both aerodynamic and mechanical considerations, and a reasonable aim is frequently to achieve a desired operating range while maximizing efficiency. For a fixed set of aerodynamic and geometric parameters there will be an optimal choice in AR that achieves a maximum efficiency. However, for a state-of-the-art aero-engine design optimality means multi-objective optimality, that is reaching the highest possible efficiency for a number of operating points while achieving a sufficient stability margin. To this end, the influence of the AR on the performance of the first rotor row of a multistage multi-objective high-speed compressor design is analyzed. A careful setup of the high-speed aerodynamic design problem allows the effect of the AR to be isolated. Close to the optimal AR, only a modest efficiency variation is observed, but a considerable change in compressor stability margin (SM) is noted. Decreasing the AR allows for an increasing efficiency, but at the expense of a reduced surge margin. This allows the designer to trade efficiency for stability. Increasing the AR, however, is shown to reduce both surge margin and efficiency, hence a distinct optimality in stability is observed for the analyzed rotor blade row. In this work, the optimality in surge margin with respect to AR is observed whereas a close to optimal efficiency. The predicted range from AR=1.10 to AR=1.64, is only indicative, considering that the definition of a multi-objective optimality requires balancing efficiency and surge margin and that the choice of balancing these two criteria requires making a design choice along a pareto optimal front.

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Towards a real-time capable hybrid-twin for gas-bearing supported high-speed turbocompressors

Olmedo

Schiffmann

2023

Energy

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Thermal management for gas lubricated, high-speed turbomachinery

Cited by 5 publications

References 33 publications

Analysis of Blade Aspect Ratio’s Influence on High-Speed Axial Compressor Performance

Analysis of Blade Aspect Ratio’s Influence on High-Speed Axial Compressor Performance

Analysis of Blade Aspect Ratio Influence on High-Speed Axial Compressor Performance

Towards a real-time capable hybrid-twin for gas-bearing supported high-speed turbocompressors

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