Periodic Reporting for period 2 - IMPACT (Aircraft advanced rear end and empennage optimisation enhanced by anti-ice coatings and devices)
Période du rapport: 2022-03-01 au 2023-08-31
IMPACT answers the call JTI-CS2-2019-CfP10-LPA-01-80 entitled “Rear fuselage and empennage shape optimization including anti-icing technologies”, and the project aims to address the following challenges:
• Developing the ability to simulate 3D inflight icing simulations on swept wings and aircraft empennages, including the effects of passive anti-ice coatings and devices.
• Characterising, integrating, and exploiting passive anti-ice coatings, and advanced three-dimensional geometry and empennage configurations, with target TRL 5 (i.e. Icing Wind Tunnel testing).
• Developing and applying innovative aerostructural optimization methods for Advanced Rear-End (ARE) development, including passive anti-ice coatings, devices and advanced geometrical features (i.e. LEX).
• Assessing the performance of passive anti-ice coating and devices via large-scale icing wind tunnel tests and inflight icing simulation.
• Developing the ability to simulate 3D inflight icing simulations on swept wings and aircraft empennages, including the effects of passive anti-ice coatings and devices.
• Characterising, integrating, and exploiting passive anti-ice coatings, and advanced three-dimensional geometry and empennage configurations, with target TRL 5 (i.e. Icing Wind Tunnel testing).
• Developing and applying innovative aerostructural optimization methods for Advanced Rear-End (ARE) development, including passive anti-ice coatings, devices and advanced geometrical features (i.e. LEX).
• Assessing the performance of passive anti-ice coating and devices via large-scale icing wind tunnel tests and inflight icing simulation.
This section reports a concise summary of the work carried out per WP, from WP1 to WP4. WP5 and WP6 are not reported since they are non-technical.
In WP1, the state-of-the-art capability for inflight icing simulations has been established and experience has been gathered in carrying out simulations with wind tunnels, full aircraft, and part aircraft. A phenomenological model of icing surface liquid has been developed, implemented in the 3D icing multi-shot workflow, and validated. Moreover, a response surface has been developed for the ARE, to input this in WP3, and account for icing effects in the aero structural optimization workflow.
In WP2, commercially available passive anti-icing coatings are characterized in the lab according to a TRL 3 assessment program, split into 3 rounds of assessment. Based on the results achieved in the lab, coatings have been ranked, and best-performing coatings scaled up for the Icing Wind Tunnel TRL 5 characterization campaign.
In WP3, a preliminary aerodynamic investigation to define the key parameters affecting the aerodynamic characteristics of the proposed ARE concept has been performed through CFD-RANS simulations. A knowledge-based parametrization approach has been developed for both the fuselage cross-section manipulation and tailplane and LEX device. A first optimized fuselage and tail and LEX arrangement has been achieved, and the effects of icing on the ARE (including LeX) are included from WP1. Finally, WP3 has released a full multi-disciplinary optimization workflow and toolset (i.e. JPAD).
In WP4, the icing wind tunnel test campaign has been executed over 10 wind tunnel days, of which 8 icing days (2 days on a NACA 23012 straight profile, and 6 days on a NACA 3421 swept profile – straight and undulated leading edge), resulting in producing 36 icing points. The model manufacturing (NACA 3421) has been subject to multiple delays, shifting the D4.1 from Aug. 2022 to March 2023. However, the consortium has managed to perform the campaign in the allocated slot (25/10/2022 07/10/2022), matching in full its technical objectives.
In WP1, the state-of-the-art capability for inflight icing simulations has been established and experience has been gathered in carrying out simulations with wind tunnels, full aircraft, and part aircraft. A phenomenological model of icing surface liquid has been developed, implemented in the 3D icing multi-shot workflow, and validated. Moreover, a response surface has been developed for the ARE, to input this in WP3, and account for icing effects in the aero structural optimization workflow.
In WP2, commercially available passive anti-icing coatings are characterized in the lab according to a TRL 3 assessment program, split into 3 rounds of assessment. Based on the results achieved in the lab, coatings have been ranked, and best-performing coatings scaled up for the Icing Wind Tunnel TRL 5 characterization campaign.
In WP3, a preliminary aerodynamic investigation to define the key parameters affecting the aerodynamic characteristics of the proposed ARE concept has been performed through CFD-RANS simulations. A knowledge-based parametrization approach has been developed for both the fuselage cross-section manipulation and tailplane and LEX device. A first optimized fuselage and tail and LEX arrangement has been achieved, and the effects of icing on the ARE (including LeX) are included from WP1. Finally, WP3 has released a full multi-disciplinary optimization workflow and toolset (i.e. JPAD).
In WP4, the icing wind tunnel test campaign has been executed over 10 wind tunnel days, of which 8 icing days (2 days on a NACA 23012 straight profile, and 6 days on a NACA 3421 swept profile – straight and undulated leading edge), resulting in producing 36 icing points. The model manufacturing (NACA 3421) has been subject to multiple delays, shifting the D4.1 from Aug. 2022 to March 2023. However, the consortium has managed to perform the campaign in the allocated slot (25/10/2022 07/10/2022), matching in full its technical objectives.
The progress beyond the state of the art from the IMPACT project can be summarised as follows:
• 3D icing simulation (WP1): Progress beyond the state of the art in this work package has been the further development and validation of a phenomenological model, in particular, the inclusion of substrate liquid droplet and rivulet flow with phase change to ice with consideration of the effects of liquid-substrate contact angle and impinging droplet impact effects with sticking, splashing and rebound; development of a simplified advanced model for substrate flow and ice accretion which includes droplet flow and phase change mechanisms as well as a film flow and phase change mechanism, thus including the effects of hydrophilicity and hydrophobicity via the water contact angle; a workflow for and experience gained in the calculation and application of icing simulation and associated performance degradation in the design of large passenger aircraft.
• Anti-ice coatings and devices (WP2): The project aims to identify the best market available anti-icing coatings. In the initial scouting action, a broad range of potential coatings was identified and the most promising were characterized according to a TRL 3 test plan. The criteria of the TRL 3 assessment, provided by Airbus, help AAC to understand the needs of the aerospace industry in terms of durability and functionality of coatings and is considered by AAC in their own developments. Coatings developed by AAC were included in the WP 2 actions and underwent the same TRL 3 assessment. The scouting and characterization action carried out in WP2 resulted in a comprehensive comparison of market-available coatings. With the selection of the top performers for wind tunnel testing (WP4) for the first time a market and laboratory study were combined with a test campaign in a climatic wind tunnel. This allows the correlation of laboratory characterization results to be related to simulated real-world conditions of a climatic wind tunnel. The results from this combined characterization will have an impact on the future role of coatings for anti-icing purposes.
• Aerodynamic and aero structural optimization (WP3): The project aims to reduce the weight of the fuselage rear end and empennage through an innovative concept based on a forward-swept horizontal tail. This solution allows for the installation of a horizontal empennage without the need for a fuselage cut-out, resulting in a significant weight reduction. The work conducted in the project has led to an optimized rear-end layout with the same aerodynamic performance as the reference conventional arrangement but with a reduced tailplane area (-5%) achieved through the addition of a specifically designed and optimized LEX device, intended to work in conjunction with a forward-swept tail. A surrogate model has been developed to predict the elastic effects of the tail on its aerodynamics, allowing for the consideration of these effects in the preliminary design and sizing phase. This reduces the development time for innovative tail arrangements. Innovative aerostructural optimization techniques, utilizing the coupling between commercial high-fidelity solvers for CFD and FEM analysis based on the adjoint technique targeting macro design parameters, have been developed and used to further optimize the tailplane's structural layout. Additional aerostructural optimization has revealed the potential for a further weight reduction of about -6% at the tailplane level, resulting in a total weight reduction at the component level of about -10%. This, in turn, leads to a potential fuel savings of -1% at the aircraft level when compared to the 2019 state-of-the-art jet aircraft, such as the A320neo.
• Model manufacturing and IWT testing (WP4): the impact generated by WP4 is mostly constituted by the scientific value of the database produced. The latter not only constitutes the most advanced and complete research database for 3D icing including coating available worldwide, shedding light on the state-of-the-art performance of coating technology for rear-end applications, but it also constitutes a reference for validating 3D ice accretion codes, including coating. The database itself will likely be used for 10-15 years after the project, generating impact across Horizon Europe (2021-2027) and subsequent (2028+) research framework programs (including Clean Aviation and subsequent JU).
• 3D icing simulation (WP1): Progress beyond the state of the art in this work package has been the further development and validation of a phenomenological model, in particular, the inclusion of substrate liquid droplet and rivulet flow with phase change to ice with consideration of the effects of liquid-substrate contact angle and impinging droplet impact effects with sticking, splashing and rebound; development of a simplified advanced model for substrate flow and ice accretion which includes droplet flow and phase change mechanisms as well as a film flow and phase change mechanism, thus including the effects of hydrophilicity and hydrophobicity via the water contact angle; a workflow for and experience gained in the calculation and application of icing simulation and associated performance degradation in the design of large passenger aircraft.
• Anti-ice coatings and devices (WP2): The project aims to identify the best market available anti-icing coatings. In the initial scouting action, a broad range of potential coatings was identified and the most promising were characterized according to a TRL 3 test plan. The criteria of the TRL 3 assessment, provided by Airbus, help AAC to understand the needs of the aerospace industry in terms of durability and functionality of coatings and is considered by AAC in their own developments. Coatings developed by AAC were included in the WP 2 actions and underwent the same TRL 3 assessment. The scouting and characterization action carried out in WP2 resulted in a comprehensive comparison of market-available coatings. With the selection of the top performers for wind tunnel testing (WP4) for the first time a market and laboratory study were combined with a test campaign in a climatic wind tunnel. This allows the correlation of laboratory characterization results to be related to simulated real-world conditions of a climatic wind tunnel. The results from this combined characterization will have an impact on the future role of coatings for anti-icing purposes.
• Aerodynamic and aero structural optimization (WP3): The project aims to reduce the weight of the fuselage rear end and empennage through an innovative concept based on a forward-swept horizontal tail. This solution allows for the installation of a horizontal empennage without the need for a fuselage cut-out, resulting in a significant weight reduction. The work conducted in the project has led to an optimized rear-end layout with the same aerodynamic performance as the reference conventional arrangement but with a reduced tailplane area (-5%) achieved through the addition of a specifically designed and optimized LEX device, intended to work in conjunction with a forward-swept tail. A surrogate model has been developed to predict the elastic effects of the tail on its aerodynamics, allowing for the consideration of these effects in the preliminary design and sizing phase. This reduces the development time for innovative tail arrangements. Innovative aerostructural optimization techniques, utilizing the coupling between commercial high-fidelity solvers for CFD and FEM analysis based on the adjoint technique targeting macro design parameters, have been developed and used to further optimize the tailplane's structural layout. Additional aerostructural optimization has revealed the potential for a further weight reduction of about -6% at the tailplane level, resulting in a total weight reduction at the component level of about -10%. This, in turn, leads to a potential fuel savings of -1% at the aircraft level when compared to the 2019 state-of-the-art jet aircraft, such as the A320neo.
• Model manufacturing and IWT testing (WP4): the impact generated by WP4 is mostly constituted by the scientific value of the database produced. The latter not only constitutes the most advanced and complete research database for 3D icing including coating available worldwide, shedding light on the state-of-the-art performance of coating technology for rear-end applications, but it also constitutes a reference for validating 3D ice accretion codes, including coating. The database itself will likely be used for 10-15 years after the project, generating impact across Horizon Europe (2021-2027) and subsequent (2028+) research framework programs (including Clean Aviation and subsequent JU).