Development of simulation methods and tools to predict the idle and sub-idle behavior of future large Very High Bypass Ratio geared civil turbofan engines.

Project Information

PROTEUS

Grant agreement ID: 785349

DOI

10.3030/785349

Project closed

EC signature date 31 January 2018

Start date 5 February 2018

End date 4 October 2021

Funded under

• SOCIETAL CHALLENGES - Smart, Green And Integrated Transport

Total cost

€ 1 112 715,00

EU contribution

€ 1 112 715,00

Coordinated by

CRANFIELD UNIVERSITY
United Kingdom

Periodic Reporting for period 2 - PROTEUS (Development of simulation methods and tools to predict the idle and sub-idle behavior of future large Very High Bypass Ratio geared civil turbofan engines.)

Reporting period: 2019-08-05 to 2021-10-04

Summary of the context and overall objectives of the project

Clean Sky 2 identifies the Very High Bypass Ratio (VHBR) geared turbofan engines amongst the main candidates to reduce aviation’s impact on environmental pollution for near-future large civil aircraft applications. Innovative technologies for VHBR geared turbofans are expected to improve fuel efficiency by more than 25% with a view towards achieving the ACARE Flightpath 2050 targets. Despite the potential benefits of the new VHBR geared engine architectures, specific challenges and limitations have been identified in terms of the performance at the edges of the operating envelope, such as idle and sub-idle operation.

The project PROTEUS (PeRformance & Operability of Turbofan Engines Under Sub-idle) focused on the research and development of tools and methods capable of predicting the idle and sub-idle performance and operability of VHBR geared turbofan engines. This was achieved through detailed component aerodynamic performance characterization of validated high-order methods, which were subsequently reduced to 0D, and integrated for rapid whole-engine analysis. Through a better understanding of the idle and sub-idle performance of the next generation of large turbofans, project PROTEUS directly contributes towards enabling the Topic Manager, Rolls-Royce plc, and the European aviation industry meet Flightpath 2050 targets. The work also enables sub-idle considerations to be included in the engine’s preliminary design process and aid in certification.
PROTEUS capitalises on several in-house methods, developed by the Consortium partners, for idle and sub-idle component performance analysis and representation. The Consortium comprised three Universities: Cranfield University (CU) in the UK (Consortium Lead), University of Cambridge (UCAM) in the UK and the Karlsruhe Institute of Technology (KIT) in Germany. (See Figure 1).

The overall objectives set to achieve the aim of this work are described as follows:

1.Improve understanding on axial-flow compressor operation under idle and sub-idle conditions and develop methods to predict sub-idle performance including the effects of bleed valves and variable geometry, heat soakage and stall drop-in during cranking and light-up.
2.Understand staged lean-burn combustor operability within a VHBR geared turbofan at sub-idle conditions and the effect of spray pattern and heat release on the combustor performance.
3.Understand the idle and sub-idle performance of the LP system by analysing fan-intake interactions, installation effects from the wing and aircraft on the exit pressure field, and turbine performance.
4.Integration of methods and tools for component characterisation in NPSS to calculate whole-engine performance at sub-idle and idle conditions.

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

The work performed in the overall PROTEUS project can be summarised with the completion of every objective related to each Work Package as follows:

WP2: Compressor Performance and Operability at Idle and Sub-idle Conditions.
Objective achieved. Robust compressor sub-idle performance methodology developed including effect of bleeds and variable geometry.

WP3. Combustor Performance and Operability at Idle and Sub-idle Conditions.
Objective achieved. Combustor sub-idle efficiency model obtained from high-fidelity methods.

WP4. LP System Performance and Operability at Idle and Sub-idle Conditions.
Objective achieved. Independent low-order sub-idle performance methods developed for the intake, bypass & core nozzles, fan/OGV/ESS and turbines.

WP5. Whole-Engine Integration.
Objective achieved. Low-order characterisation methods integrated into the R-R NPSS platform and the ability to simulate whole-engine steady-state and transient relight in NPSS for a VHBR turbofan engine and for the UltraFan™ engine demonstrator models.

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)

Project Impact

The PROTEUS project impact beyond the state-of-the-art can be summarized in 2 major contributions:

• Development of component low-order method capabilities for the fan, nozzles, compressor and turbines and an identified high-order method for the combustor.
• Demonstration of the ability to simulate whole-engine steady-state windmill and transient relight in NPSS. This capability was validated on a modern VHBR turbofan engine model and applied to the UltraFan™ DEMO engine model.

Clean Sky High-level Goals Contribution

The VHBR geared turbofan UltraFan™ engine DEMO design and development was conducted under the WP 6 of the engines Integrated Technology Demonstrator (ITD) of Clean Sky 2. The expectations for this VHBR geared turbofan engine demonstrator within this activity are the following:

• UltraFan™ engine to service in the near-future large civil aircraft applications.
• UltraFan™ engine to improve efficiency by 25% compared to the current technology.

The final product of the PROTEUS project is the NPSS UltraFan™ whole-engine performance tool, which supports the UltraFan™ engine DEMO windmill-relight certification. In this context, the PROTEUS final product directly contributes towards enabling the Topic Manager and the European aviation industry meet the Flightpath 2050 targets in terms of CO2 and NOx emissions reduction.

The NPSS UltraFan™ whole-engine performance model as the final PROTEUS product supports the UltraFan™ DEMO performance assessment and contributes to fulfil the Strategic Research and Innovation (SRIA) challenges:

• Maintain and extend industrial leadership.
- Development of new knowledge for VHBR geared turbofan engines, hence increase competitiveness & lead market.
- Integration of an expert & specialised research team across partners.

• Ensure safety and security.
- Quantify component-level performance during altitude relight events.
- Quantify assessment of the whole-engine under sub-idle for more efficient ground start-up and robust altitude-relight.

• Prioritise research, testing capabilities and education.
- Supports the development of the European network of research centres of excellence in relation to future VHBR geared turbofans.
- Development and validation of multi-disciplinary performance simulation tools for future propulsion systems design and integration.
- Identification of areas where further experimental validation might be required.
- Increase the skills & knowledge of staff & students and enriching the talent pool available to EU aerospace industry.

Contribution to the Topic Manager’s DEMO

A UltraFan™ engine model now exists within the R-R NPSS platform and is ready to be used for steady-state and transient windmill relight conditions. The R-R NPSS UltraFan™ engine model demonstrates the ability of the Topic Manager’s DEMO to relight towards meeting the engine altitude windmill-relight certification requirements.

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