STO-Activities: (no title)
Activity title:
Active flow control Applied to Air Inlets for High-speed Propulsion Systems
Activity Reference:
AVT-402
Panel:
AVT
Security Classification:
NATO UNCLASSIFIED
Status:
Planning
Activity type:
RTG
Start date:
2025-01-01T00:00:00Z
Actual End date:
2027-12-31T00:00:00Z
Keywords:
Counterhypersonics, Highspeed air inlets, Highspeed air vehicles, Interceptor concepts, Plasma flow control, Propulsion Systems
Background:
The advantages of long-range high-speed flights using airbreathing propulsion against time-critical targets is well- known and air inlets are key component of any airbreathing engines since they control the quality and amount of air delivered to the downstream propulsion system. The advancement of high-speed propulsion demands a seamless integration of aerodynamics and propulsion components.
Air inlet systems for embedded jet, ramjet, and scramjet engines usually have diverging and contoured S-shaped ducts for structural and aerodynamic reasons. The ratios of length, diffusion, cross-sectional area, entrance aspect and offset, and the centerline curvatures all vary with the design of an air vehicle. The flow in S-ducts is complex due to curvature, cross-section axial evolution, and diffusion, all of which result in reductions in static pressure recovery, and increases in total pressure loss, exit flow distortion and swirl. Degraded flow in S-duct inlets decreases overall efficiency, stability margin, and safety of the high-speed air vehicle’s propulsion system.
The AVT-190, 254 (finished) and the AVT-344 activities have concluded that active flow control technologies can improve and enhance flow in such geometries, including those of inlets at all speeds. Improvements on the flow quality at the engine face provided by active flow control strategies, ultimately would increase the flight envelope and maneuverability of air vehicles, which are required features on interceptor concepts against hypersonic threats. In the following paragraph the capability and contribution of the member institutes, relevant to the committee activities, is given.
The Royal Military College of Canada (RMC) has carried out a series of tests on inlets in the RMC transient transonic wind tunnel facility in collaboration with DRDC-Valcartier Research Center (VRC). RMC’s role in that project involved the determination of aerodynamic losses and flow distortion encountered in S-duct inlets commonly installed in high-subsonic air vehicles. Without detailed knowledge of threats, a parametric approach was adopted to determine the relative influence of duct geometric features on aerodynamic performance of an inlet. In the course of that research, potential design approaches were proposed to reduce detrimental effects of flow distortion. While passive flow control has been at the heart of RMC’s research, exploration of a promising active flow control technique using Plasma Actuators (PA) should be pursued. The basic principle of PA operation, electronics, fabrication, modeling, visual characteristics, and optical measurement techniques are available in literature published in last two decades and are reported in the TR-AVT-190 and 254 respectively.
Objectives:
The scientific objectives involve systematic investigation and experimentation to gain knowledge and understanding about high-speed vehicle propulsion inlet systems. Key objectives include: 1. Fundamental Understanding: Studying the physics of inlet aerodynamics and propulsion efficiency at high speeds. 2. Flow Control Mechanisms: Investigating methods to control boundary layers and to mitigate losses due to secondary flows. 3. Quantitative Analysis: Assessing the impact of inlet flow distortion on vehicle performance. 4. Validation and Verification: Ensuring the accuracy of theoretical models through experimental data. 5. Performance Improvement: Developing efficient methods to enhance high-speed vehicle performance. 6. Interdisciplinary Research: Collaborating across disciplines for innovative solutions. 7. Knowledge Dissemination: Sharing findings with the scientific community through publications and conferences.
Topics:
The activity will cover the following major scientific topic areas, each directly related to the previously stated relevance and objectives:
High-subsonic, Supersonic and Hypersonic Flow Phenomena: This topic involves the study of fluid dynamics in the inlet of high-speed air vehicles.
Flow Separation and Control: This topic area focuses on the mechanisms and factors leading to flow distortion and instability in inlet contours and methods to control and mitigate it. Plasma actuators and other flow control technologies will be explored to achieve the objective of improving performance and reducing adverse inlet performance contributions.
Total Pressure Recovery: Researchers will study methods to enhance inlet total pressure recovery, which directly influences engine inlet efficiency. Techniques for optimizing inlet/diffuser designs and for mitigating flow distortion, including separation, will be investigated to achieve higher inlet total pressure recovery.
These scientific topic areas align with the relevance and objectives of the activity, addressing the challenges faced in high-speed air vehicle aerodynamics and propulsion. Through in-depth exploration and research in these areas, researchers can contribute to advancements that improve the performance, efficiency, operability and safety of high-speed air vehicles, as well as to facilitate innovations in other related fields.
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Created at 23/10/2023 17:00 by System Account
Last modified at 16/05/2024 13:00 by System Account
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