High Speed Compressor Design

Lucilene Moraes da Silva

Post Doctoral Researcher

Department of Mechanics and Maritime Sciences

Division of Fluid Dynamics

Workshop, Marine Technology and Fluid Dynamics

March 16, 2020

March 16, 2020 2

• Motivation

• Design features: conceptual / preliminary design and analysis

• Design challenges that are encountered when developing a high-speed axial

compressor

• Design Framework

• Work in-progress

Topics covered

Department of Mechanics and Maritime Sciences

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Typical application Type of flow Pressure ratio per stage Efficiency per stage

Industrial Subsonic 1.05 - 1.2 88 - 92%

Aerospace Transonic 1.15 – 2.0 84 - 88%

EJ200 EngineEurofighter Typhoon Transonic Compressor

Motivation

March 16, 2020 Department of Mechanics and Maritime Sciences

4March 16, 2020 Department of Mechanics and Maritime Sciences

Motivation

Requirements of next-generation fighter

aircraft:

• Maximum range and high mission

flexibility.

• Long operating times, and

predictable life-cycle costs that are

as low as possible, plus a low radar

signature.

https://www.mtu.de/the-new-european-fighter-jet/

Improvements of high speed compressor

design:

• It allows higher pressure ratios per single-

stage, resulting in reduction of the engine

weight and size and, therefore, investment

and operational costs.

• Small increment in efficiency, can result in

huge savings in fuel costs, improvement of

rotor stability towards near stall conditions,

resulting in a wider working range.

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Design Features

March 16, 2020 Department of Mechanics and Maritime Sciences

Lejon, C. Et al. Multidisciplinary Design of a Three Stage High

Speed Booster. GT2017-64466

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In order to maintain good flow over the blade

certain conditions must be meet.

• The relative flow angle and the inlet blade angle

must be close to prevent flow separation from the

blade.

• The turning angle (deflection) must be keep quite

small, or the flow will also separate from the blade.

• The relative flow velocity must not be too close to

the speed of sound. This is to prevent shock waves

from forming on the blade.

Design Challenges

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shock waves

Intense secondary flows

Shock/boundary layer interaction

Development of blockage

Stall /flow separation

Flow interaction at rotor tip clearance

Reduction of Compressor Performance

Design Challenges

March 16, 2020 Department of Mechanics and Maritime Sciences

Entropy Generation

(Losses)

Saito, S. et al. Mechanisms and quantitative evaluation of flow loss

generation in a multi-stage transonic axial compressor. GT2019-90439

Department of Mechanics and Maritime Sciences 8March 16, 2020

Design Challenges

• Developing an efficient high speed axial compressor multistage design

• Loss models to predict the profile, secondary, transient and leakages losses.

• Accurately prediction of shock waves, experimental and numerical.

• Prediction of the surge limit.

Hergt, A. et al. The Present Challenge of Transonic Compressor Blade Design. Journal of Turbomachinery. September 2019, Vol. 141

Sketch of the numerical aerodynamic design point, numerical stall onset and comparison of the numerical and experimental stall

margin, respectively.

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Design Framework

March 16, 2020 Department of Mechanics and Maritime Sciences

Preliminary Design Blade Generation

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Design Framework

CFD Analysis

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Work in-progress

• Working with re-design an stage of axial compressor using the design

framework aiming to improve the stage efficiency through rotor blade

optimization.

• Working with a conference article about optimal aspect ratio for high speed

compressor.

• Working how to assessment and breakdown of losses in high speed

compressor.

March 16, 2020 Department of Mechanics and Maritime Sciences

Thank you very much for listening!