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Mitigation of flow separation in a highly bent intake duct with active and passive flow control

Published online by Cambridge University Press:  17 January 2025

P. Max Open the ORCID record for P. Max [Opens in a new window] ,
M. Stößel ,
D. Kožulović  and
M. Krummenauer
P. Max*
Affiliation:
Department of Aerospace Engineering, Institute of Jet Propulsion, University of the Bundeswehr Munich, Munich, Germany
M. Stößel
Affiliation:
Department of Aerospace Engineering, Institute of Jet Propulsion, University of the Bundeswehr Munich, Munich, Germany
D. Kožulović
Affiliation:
Department of Aerospace Engineering, Institute of Jet Propulsion, University of the Bundeswehr Munich, Munich, Germany
M. Krummenauer
Affiliation:
Bundeswehr Technical Centre for Aircraft and Aeronautical Equipment, Manching, Germany
*
Corresponding author: P. Max; Email: [email protected]
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Abstract

Typically, the fuselage of a modern military aircraft is designed in such a way that the propulsion system is integrated into it. The main reasons are reduction of installation space and minimisation of radar signature. Those requirements can be achieved by using highly bent engine intakes, which are occluding a direct line of sight to the compressor system. Depending on their design, secondary flows and flow separation can be expected due to the strong curvature of the intake system. In this study, a serpentine intake in front of the Larzac 04 test engine is investigated experimentally and its performance compared with and without flow stabilising measures. In detail, a configuration with vortex generators was compared experimentally with a configuration of active flow control by injected air. In order to analyse and compare the efficiency of both systems, the dimensionless total pressure coefficient, the distortion coefficient (DC60) and detailed surface pressure distributions as well as the aerodynamic interface plane are evaluated. In addition, different throttle lines were recorded for surge line evaluation of the low pressure compressor of the Larzac engine and compared for each flow-stabilising measure investigated. It was found that the application of injecting air showed a larger improvement in surge margin and reduction in distortion coefficients compared to the passive flow control.

Keywords

highly bent engine intakesactive flow controlpassive flow control
Type
Research Article
Information
The Aeronautical Journal , First View , pp. 1 - 18
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Copyright
© The Author(s), 2025. Published by Cambridge University Press on behalf of Royal Aeronautical Society

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