Periodic Reporting for period 3 - ARTEM (Aircraft noise Reduction Technologies and related Environmental iMpact)
Periodo di rendicontazione: 2020-12-01 al 2022-05-31
ARTEM was a four-year research project, started in December 2017, and ended successfully in May 2022 including a 6 month "no-cost-involved" extension to compensate for the impact of the COVID pandemic. ARTEM was devoted to the development of novel noise reduction technologies for aircrafts expected to enter service between 2035 and 2050.
The need to further reduce the noise emissions of commercial aircraft is obvious considering current annoyance and expected growth of air traffic. ARTEM was set up in order to help closing the gap between noise reductions obtained by current technologies and the 2050 goals of ACARE, i.e. a noise reduction of 65% compared to year 2000 value.
Therefore, ARTEM develops innovative ideas and concepts for efficient noise reduction, co called “Generation 3” noise reduction technologies, to a technology readiness level of 3 (experimental proof of concept) or 4 (technology validated in lab).
Within the project it is taken into account, that novel aircrafts expected for 2035 and 2050, are likely to have different configurations. The noise signature of these configurations will be strongly influenced by the interaction of several aircraft components. The detailed understanding of those interactions is one focus of ARTEM and basis for further noise reduction. Secondly, ARTEM addresses innovative concepts for the efficient damping of noise by dissipative surface materials and novel liners. Technologies were coupled to future aircraft configurations prediciting the expected benefit.
Initiated by EREA, ARTEM brought together the expertise of a large and diverse consortium consisting of 24 partners: national research centers for aviation research, universities, small-and medium-sized enterprises, and major European aircraft industry companies.
The need to further reduce the noise emissions of commercial aircraft is obvious considering current annoyance and expected growth of air traffic. ARTEM was set up in order to help closing the gap between noise reductions obtained by current technologies and the 2050 goals of ACARE, i.e. a noise reduction of 65% compared to year 2000 value.
Therefore, ARTEM develops innovative ideas and concepts for efficient noise reduction, co called “Generation 3” noise reduction technologies, to a technology readiness level of 3 (experimental proof of concept) or 4 (technology validated in lab).
Within the project it is taken into account, that novel aircrafts expected for 2035 and 2050, are likely to have different configurations. The noise signature of these configurations will be strongly influenced by the interaction of several aircraft components. The detailed understanding of those interactions is one focus of ARTEM and basis for further noise reduction. Secondly, ARTEM addresses innovative concepts for the efficient damping of noise by dissipative surface materials and novel liners. Technologies were coupled to future aircraft configurations prediciting the expected benefit.
Initiated by EREA, ARTEM brought together the expertise of a large and diverse consortium consisting of 24 partners: national research centers for aviation research, universities, small-and medium-sized enterprises, and major European aircraft industry companies.
ARTEM has successfully explored a large variety of concepts for passive and active noise reduction. Two liner concepts, namely the multi-focal and the slanted septum liner concept proved exceptionally good progress. An expected benefit of 0.7-0.9 EPNdB on aircraft level was estimated for a 2025 large long-range aircraft during the industrial assessment. All other concepts have also made significant progress in maturation reaching the expected TRLs of 3-4 depending on starting point.
Shielding modelling has been improved and finally successfully applied demonstrating the tremendous benefit with respect to noise reductions for ground observers if propulsion systems are placed on top of an aircraft structure – in particular here for blended wing body aircraft.
The complex flow and noise generation phenomena associated with conventional high-lift systems have been successfully modelled and noise reduction demonstrated by design variation like the very long chord slat (VLCS). The variety of modelling and prediction approaches from quick 2-D tools capable to handle many design variations during an optimization process and high-fidelity simulations including (Overset-)LES for in-depth analysis of noise generation mechanism will prove very useful for future aircraft system development work. Other means for noise reductions (serrations, finlets, porous inserts, etc) have been investigated numerically, experimentally and proved good results on component level, but lower impact during assessment on full aircraft scale.
The boundary layer ingestion concept (BLI), which is anticipated to reduce fuel consumption for “tube&wing” aircraft significantly, has been addressed in a comprehensive receiving great attention in the community. Tools from low-fidelity modelling to extensive numerical simulations on full aircraft scale using ONERA NOVA and NAUTILIUS platform have been applied. It was coherently demonstrated, that the inflow distortions associated with this concept are prone to increase the radiated propulsion noise – mainly fan noise – significantly. Great care is needed in the design of the inlet duct system to reduce inflow distortion as much as possible with extensive application of liners having the capability to further reduce or avoid any noise penalties.
For aircraft landing systems, a large campaign involved experimental and numerical work on detailed source analysis and promising reduction means as meshes, screens, fairing design, and porous inserts. While already demonstrating some potential noise reduction on model scale and during full aircraft assessment, the work performed in ARTEM constitutes a profound basis for on-going H2020 project INVENTOR work.
As a basis for distributed electric propulsion systems, a detailed study of mutual interaction effects of closely spaced rotors, and between rotor and wing structure has been performed in ARTEM. A purpose-build highly modular test setup consisting of a wing section and 3 propellers mountable in pusher and puller configuration was used to build-up a huge experimental data base and subsequent data processing and prediction tool development.
For the early design phase aircraft development, a robust multi-dimensional design optimization tool (MDO) was improved and subsequently applied to design two blended-wing body (BWB) aircraft configurations:
BOLT: a long-range BWB, REBEL: a short-range BWB aircraft with either classical UHBR engines (REBEL-C) or a distributed hybrid electrical propulsion system (REBEL-HEP).
The assessment for promising technologies on a CleanSky2-derived platforms for short-/medium range (SMR) and long-range (LR) aircraft has been performed by Airbus while a specific business jet platform was used by Dassault Aviation for the same task.
Based on noise predictions of the novel aircraft configurations, auralizations have been generated and used for comparative listening test concentrating also on psycho-acoustic aspects of annoyance of future aircraft noise.
Shielding modelling has been improved and finally successfully applied demonstrating the tremendous benefit with respect to noise reductions for ground observers if propulsion systems are placed on top of an aircraft structure – in particular here for blended wing body aircraft.
The complex flow and noise generation phenomena associated with conventional high-lift systems have been successfully modelled and noise reduction demonstrated by design variation like the very long chord slat (VLCS). The variety of modelling and prediction approaches from quick 2-D tools capable to handle many design variations during an optimization process and high-fidelity simulations including (Overset-)LES for in-depth analysis of noise generation mechanism will prove very useful for future aircraft system development work. Other means for noise reductions (serrations, finlets, porous inserts, etc) have been investigated numerically, experimentally and proved good results on component level, but lower impact during assessment on full aircraft scale.
The boundary layer ingestion concept (BLI), which is anticipated to reduce fuel consumption for “tube&wing” aircraft significantly, has been addressed in a comprehensive receiving great attention in the community. Tools from low-fidelity modelling to extensive numerical simulations on full aircraft scale using ONERA NOVA and NAUTILIUS platform have been applied. It was coherently demonstrated, that the inflow distortions associated with this concept are prone to increase the radiated propulsion noise – mainly fan noise – significantly. Great care is needed in the design of the inlet duct system to reduce inflow distortion as much as possible with extensive application of liners having the capability to further reduce or avoid any noise penalties.
For aircraft landing systems, a large campaign involved experimental and numerical work on detailed source analysis and promising reduction means as meshes, screens, fairing design, and porous inserts. While already demonstrating some potential noise reduction on model scale and during full aircraft assessment, the work performed in ARTEM constitutes a profound basis for on-going H2020 project INVENTOR work.
As a basis for distributed electric propulsion systems, a detailed study of mutual interaction effects of closely spaced rotors, and between rotor and wing structure has been performed in ARTEM. A purpose-build highly modular test setup consisting of a wing section and 3 propellers mountable in pusher and puller configuration was used to build-up a huge experimental data base and subsequent data processing and prediction tool development.
For the early design phase aircraft development, a robust multi-dimensional design optimization tool (MDO) was improved and subsequently applied to design two blended-wing body (BWB) aircraft configurations:
BOLT: a long-range BWB, REBEL: a short-range BWB aircraft with either classical UHBR engines (REBEL-C) or a distributed hybrid electrical propulsion system (REBEL-HEP).
The assessment for promising technologies on a CleanSky2-derived platforms for short-/medium range (SMR) and long-range (LR) aircraft has been performed by Airbus while a specific business jet platform was used by Dassault Aviation for the same task.
Based on noise predictions of the novel aircraft configurations, auralizations have been generated and used for comparative listening test concentrating also on psycho-acoustic aspects of annoyance of future aircraft noise.
ARTEM supports the maturation of low TRL “Generation 3” technology solutions aimed at 2035 / 2050 noise reduction targets to initiate a new research phase beyond the successful Silence(R), OPENAIR, and Clean Sky programs.
The interaction noise effects considered in ARTEM are of highest relevance for current and future aircraft configuration, as isolated reduction means do often not obtain the expected noise reduction.
Following results have been reached at project end:
• Description of effects and associated noise reduction methods by design or other means for interaction noise sources encountered at novel configurations
• Synthesis on novel liners and absorption concepts at TRL3-4 and assessment of their acoustic performance (broadband, low-frequency, overall damping) under flow conditions
• Assessment of the impact of investigated noise reduction technologies for ACARE noise targets
An assessment has been made with respect to applicability of ARTEM concepts and methods for near-/mid-term applications. Relevant steps and the need for further research and development has been identified.
Building on a close cooperation with parallel-running H2020 project ANIMA, a chapter on future aircraft design and associated noise implications has been contributed to the open access book “Aviation Noise Impact Management” (Springer, 2022), which has exceeded the total of 25’000 downloads already after 6 months.
ARTEM results and achievements will form the basis for a large number of future higher TRL research activities on national and international level, as for instance the Horizon Europe program of the EC or Clean Aviation activities.
The interaction noise effects considered in ARTEM are of highest relevance for current and future aircraft configuration, as isolated reduction means do often not obtain the expected noise reduction.
Following results have been reached at project end:
• Description of effects and associated noise reduction methods by design or other means for interaction noise sources encountered at novel configurations
• Synthesis on novel liners and absorption concepts at TRL3-4 and assessment of their acoustic performance (broadband, low-frequency, overall damping) under flow conditions
• Assessment of the impact of investigated noise reduction technologies for ACARE noise targets
An assessment has been made with respect to applicability of ARTEM concepts and methods for near-/mid-term applications. Relevant steps and the need for further research and development has been identified.
Building on a close cooperation with parallel-running H2020 project ANIMA, a chapter on future aircraft design and associated noise implications has been contributed to the open access book “Aviation Noise Impact Management” (Springer, 2022), which has exceeded the total of 25’000 downloads already after 6 months.
ARTEM results and achievements will form the basis for a large number of future higher TRL research activities on national and international level, as for instance the Horizon Europe program of the EC or Clean Aviation activities.