Experimental Aero- and Thermal investigation for a next generation Engine Exit Module

Project Information

EATEEM

Grant agreement ID: 821398

DOI

10.3030/821398

Project closed

EC signature date 25 September 2018

Start date 1 October 2018

End date 30 June 2022

Funded under

• SOCIETAL CHALLENGES - Smart, Green And Integrated Transport

Total cost

€ 799 608,75

EU contribution

€ 799 608,75

Coordinated by

CHALMERS TEKNISKA HOGSKOLA AB
Sweden

Periodic Reporting for period 3 - EATEEM (Experimental Aero- and Thermal investigation for a next generation Engine Exit Module)

Reporting period: 2021-07-01 to 2022-06-30

Summary of the context and overall objectives of the project

Beyond 2020, new efforts are required to improve the engine efficiency and fuel burn to meet the Advisory Council for Aeronautics Research in Europe (ACARE) goals for the years 2035 and 2050. The year 2050 targets aim for a 75% reduction in CO2 emissions, a 90% reduction in NOx emissions, and a 65% reduction of the perceived noise relative to engine and aircraft performance of the year 2000. It is commonly agreed that the geared turbofan engines have the potential to make a significant step towards the above targets. The Advanced Geared Engine Configuration and the Very High Bypass Ratio Turbofan are two crucial radical engine architectures selected to be matured within the ENGINES ITD of the Clean Sky 2 Programme.

To further increase the engine efficiency and reach CO2 emission targets, the expansion system is constantly challenged by reducing gas path pressure losses, widening the operational envelope, and allowing for the ever-increasing geometrical complexity of structural components. For the Turbine Rear Structure (TRS) and the Engine Exit Module (EEM), the new engine architecture imply that designs are needed that can withstand higher temperatures and temperature variations, operate under more severe LPT off-design conditions, present lower pressure losses, be lighter and shorter while still provide performance benefits.

Chalmers and GKN Aerospace Engine Systems are collaborating in this Clean Sky 2 project, won by Chalmers in the open call for partners, with GKN as the Topic Manager. A unique facility for experimental testing of engine exit modules (EEM) at engine-realistic flow conditions at Chalmers is used for testing of novel EEMs for future efficient aero-engines. The unique design of the facility includes an open test section that permits investigation of complete EEM assemblies consisting of a turbine rear structure (TRS) and a core exhaust nozzle. The facility is equipped with a 1.5 stage shrouded low-pressure turbine (LPT) providing realistic inflow to the tested EEM.

The overall concept of EATEEM is to mature expansion system technologies so that they become key enablers for reducing CO2 emissions and engine mass for the Advanced Geared Engine and Very High Bypass Ratio Turbofan configurations in the ITD work package of Clean Sky 2 Programme. Thus, EATEEM is a part of the work package defined to bring the expansion technologies to TRL 4. The EATEEM project test infrastructure will enable further research on EEM improvement and allows for the investigation of state-of-the-art EEM concepts to be used in the next generation of aero engines.

The overall objectives that have been planned and achieved in the project:

Objective 1. Proof-of-concept and laboratory validation of four novel EEM architectures.
Objective 2. Characterization of the aerodynamic performance of novel EEM architectures.
Objective 3. Investigation of the heat transfer for the Build 1 novel EEM architecture.
Objective 4. Provided input data and hardware for exploring new EEM functionalities and EEM optimization.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Project efforts have demonstrated the feasibility and benefits of novel aerodynamic EEM concepts. Main project results are:
Four EEM architectures were designed, manufactured, assembled, instrumented, and tested. Tests have been performed in a unique facility at a representative upstream LPT stage, inlet conditions, and flow Reynolds numbers for the demonstration up TRL 4 as specified in the targets.
Delivered data include highly accurate measurements for pressure and velocities at a number of planes, total pressure loss, turbulence intensity and length scale, static pressure distribution on outlet guide vanes (OGVs), maps of the separation margins, location of the laminar-turbulent transition, flow visualizations on OGVs and end-walls according to the test matrix. The data have been provided for several sectors of the TRS modules having different functionalities. State-of-the-art instrumentation was performed and validated to assess the aerodynamic characteristics of the novel EEM aerodesigns with a very high measurement accuracy: better than 0.1% for the total pressure differences, better than 1.5 Pa for multihole probe and wall pressures, and better than 1% for the axial velocity as specified in the targets.
Build 1 test section has been instrumented and measurements have been performed to provide heat transfer data. Heat transfer characteristics of the EEM Build 1 have been assessed with very high measurement accuracy, better than 0.2K for temperatures and temperature differences, resulting in the accuracy of the heat transfer coefficient better than 5% on at least 50% of the surfaces. The measurements include the study of the influence on the heat transfer of the laminar-turbulent transition location, flow separation, the flow Reynolds number, inlet swirl angle, and purge flow.
Experimental data, hardware, and professional experience from the EATEEM project have resulted in several follow-up projects on novel hydrogen-based and WET-cycle aero-engines. The project results have been disseminated in several high-quality scientific publications. The project results will help to achieve further targets which are beyond the project: to develop new functionality in the EEM for heat recuperation; to develop new functionality in the EEM for noise reduction; to develop advanced CFD methods for aero- and thermal analysis of the EEM; to develop optimization methods for the EEM with respect to component weight. Within the frame of the project, synergy is established between the EATEEM and other aircraft/aero-engine research projects: two national-program research projects (on the influence of manufacturing non-conformances on TRS performance and on hydrogen-based aero-engine) and a European research project ENABLEH2 which is focused among other topics on core exhaust heat rejection in TRS.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

CHALMERS TRS/EEM facility offers several unique opportunities compared to other rigs. Construction of the test section of CHALMERS TRS/EEM facility allows for testing the entire EEM assemblies and allows arbitrary shapes of the EEM test sections including polygonal walls. The facility is low-speed high-Reynolds number type which means continuous operation and long experimental runs for highly detailed and accurate measurements. The facility has very high stability and repeatability of setpoint parameters. To our knowledge, the EATEEM project is the first experimental EEM validation project providing a complex aero-thermal analysis of TRS modules by several accurate measurement techniques, which makes the EATEEM outcome unique in its value and data reliability. The EATEEM project gives an exceptional opportunity to push the measurement accuracies for all used measurement techniques to their upper limits by minimizing the measurement uncertainties based on our experience from previous research projects. The EATEEM provides experimental validation data for several new concepts. The EATEEM data are used for validation of new improved optimization and numerical prediction methods for aerodynamic and heat-transfer performance. Furthermore, the experimental methods and hardware from the EATEEM will be used in future research projects devoted to the development of the EEM. Within the frame of the project, synergy is established between the EATEEM and three other aero-engine research projects.

Chalmers University dedicated TRS/EEM experimental facility, with Reynolds range capability