CORDIS - EU research results

Innovative STATOR

Periodic Reporting for period 2 - InnoSTAT (Innovative STATOR)

Reporting period: 2021-04-01 to 2022-09-30

The project InnoSTAT envisages to support the aircraft industry in meeting the goals defined in Flightpath 2050 - Europe’s Vision for Aviation noise goals, where the ACARE environment objectives are defined in “Protecting the environment and the energy supply” and directly addressing aircraft noise emissions: The perceived noise emission of flying aircraft has to be reduced by 65 %, relative to the capabilities of typical new aircraft in the year 2000.

Therefore, the noise reduction measures for engine related noise from the intake, but also for rearward radiation is highly targeted by aircraft industry during the last 15 to 20 years. Most effort has been made in passive technologies for intake liner concepts, but also for the low noise design of fan and stator blades. From all the current available technologies a noise reduction related to engine sources by 6 dB can be expected, which is a big achievement, but still does not suffice to reach the goals. Thus, a further refinement of possible technologies has to be re-opened, like in the case of innovative stator technology. The proposed work of InnoSTAT consists in a systematic procedure, which has not been performed yet for considered OGV technologies. InnoSTAT will be the first project where the activities are focused on the above process with the only goal of bringing at least 3 OGV concepts to demonstrator level at TRL3 on full scale. This has not been achieved yet in any other programme for one OGV concept. The project’s objectives are

• to define 5 novel low noise stator concept designs, to develop and test them on prototype level TRL2 to TRL3,
• to select and develop 3 novel stator concepts for further advanced design, characterisation and full 3D stator stage large scale testing to TRL4,
• to define, design, and manufacture 2 demonstrator OGVs at TRL3 on full scale.

The project’s goal will be achieved in 3 major steps:

STEP1 - Testing and improving the technologies of 5 concepts on small scale prototype level.
STEP2 - Down selection of 3 technologies for further test on large scale, each as a fully equipped stator stage.
STEP3: Finally manufacturing 2 selected concept demonstrators and perform an integration study regarding engine environment.

This 48-months project with its ambitious goals will request 2,788 k€ in total. Its contribution to the noise reduction on ultra-advanced long-range and ultra-advanced short/medium range will be significant.
Between M1 and M18 the focus was mainly on the appropriate specifications and the final selection of OGV concepts for prototype manufacturing and testing. All five concepts, already pre-defined in the preparation phase of the project InnoSTAT, were confirmed according to the best available information. This was done in a final technology review, which was performed to ensure that the right technologies will be used for the test campaign of WP3. All participants were contributing and explained their technologies in-depth. Further specifications, like basic test setup definition, blade geometry, target frequencies and aerodynamic properties, were established and extensively documented. Additionally, the detailed description of the technical requirements for the OGV prototypes was provided and the specifications for the configurations to be studied in the small-scale (WP3) experimental campaign were also provided. A first preliminary design review meeting (PDR) took place in M17 of the project, representing milestone MS2.

The period from M19 to M36 was mainly dedicated to preparing the small-scale wind tunnel tests of WP3. The prototype concept of each project participant underwent a detailed design for the use in the wind tunnel setup, specifically designed for InnoSTAT. A final concept selection occurred in summer 2021 after a CDR has been held and manufactured for the test at ECL’s KCA facility. In total, 49 OGV – 5 prototype configurations and 2 references - were manufactured until mid of January 2022 and tested until the end of May 2022. Almost all of the 5 tested prototype concepts, together with the reference OGV, delivered promising acoustic results. Applying a specific selection procedure, which included the most important acoustic metrics but also taking aerodynamic performance into account, 3 concepts from the consortium were selected for the next phase of InnoSTAT, the large-scale investigations of WP4. This action accomplished the previously described STEP1.
Activities on OGV for engine noise reduction are ongoing since more than a decade. The selection of 5 different concepts, ranging from passive and active to adaptive, and developing them systematically from small-scale over large-scale into the final result: a full-scale demonstration for engine integration, is a process which goes beyond the state-of-the-art. The achievements until M36 of InnoSTAT were a clear step ahead in this aim and despite the situation of the pandemic – InnoSTAT’s first period was almost entirely covered by this global catastrophy – OGV concepts for prototype manufacturing and testing were confirmed. The remaining design constraints, such as aerodynamic loads and targeted acoustic frequencies, were clearly described, as an essential part for the concepts’ final design, manufacturing work, and extensive wind tunnel testing, which was performed in the second period. Using the experimental data, 3 OGV concepts from InnoSTAT participants were selected for the upcoming large-scale investigations, which include some re-design work and tests with a rotating laboratory fan. In this overall unified process of InnoSTAT’s scientific concept, low-noise concepts for this specific noise source of the fan-stator-interaction at a turbofan engine were systematically developed for the first time from small-scale to demonstration under premises given by InnoSTAT.

The impact from InnoSTAT will be generated by the actions, planned within the project. They will demonstrate - in a well quantified step-by-step process - the potential of establishing a technology for aircrafts’ noise reduction by providing concepts on demonstrator level, and setting the focus on novel aircraft propulsion systems, such as UHBR, that can make a significant contribution towards:

• Reduction of perceived noise by 65% in 2050 (baseline year 2000) and thus reducing the impact of Europe's air transport operations on the environment. Since aviation has a direct impact on the environment and over EU citizens’ health due to its emissions and noise to which the population is exposed.
• Production of competitive air vehicles by 2050. Aviation industry is crucial to the EU workforce (3 %) and European employment (3.7 million direct and indirect jobs). Noise is a clear metric for the competitiveness of a product. Creating an advantage in low noise technology like the innovative stator will be directly resulting in an advantage for the economy of the EU.
• The results of InnoSTAT will indirectly enabling a more ecologic and more economic turbofan engine, such as UHBR, which goes in line with acoustical shortcomings (e.g. shorter nacelle provides less space for acoustic lining, bigger fan diameter and slower rotation speed will yield low frequency noise effects, etc.).

InnoSTAT’s impact will also contribute - in this respect - to the retaining of natural resources and reducing the impact on climate by enabling novel aircraft engine architectures.
Wind tunnel test section with the cascade of 7 prototype OGV