Support to Future CROR and UHBR Propulsion System Maturation

Project Information

PropMat

Grant agreement ID: 680954

DOI

10.3030/680954

Project closed

EC signature date 14 December 2015

Start date 1 January 2016

End date 31 December 2023

Funded under

• SOCIETAL CHALLENGES - Smart, Green And Integrated Transport

Total cost

€ 2 743 488,75

EU contribution

€ 2 743 488,75

Coordinated by

STICHTING KONINKLIJK NEDERLANDS LUCHT - EN RUIMTEVAARTCENTRUM
Netherlands

Periodic Reporting for period 5 - PropMat (Support to Future CROR and UHBR Propulsion System Maturation)

Reporting period: 2022-01-01 to 2023-12-31

Summary of the context and overall objectives of the project

The leading European aircraft and aero-engine industry proceeded in Clean Sky 2 with the development of candidate low fuel burn propulsion concepts: the Ultra High Bypass Ratio turbofan (UHBR) and the Open-Rotor. The PropMat project contributed to the technology maturation of these novel propulsion concepts with:
• Innovative numerical and experimental methods and tools as needed for aerodynamic &-acoustic characterisation of aircraft concepts through simulation, wind tunnel testing, and flight testing
• Analyses and experimental results for the novel propulsion concepts for large transport aircraft (aircraft concepts and wind tunnel test bench) enabling improvement of the concepts and test bed designs

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

1) An innovative chase aircraft acoustic in-flight measurement methodology was developed. The noise of a flying demonstrator of an innovative engine configuration is measured accurately in all directions and at various distances, in various operational conditions. The method was validated with NLR’s Citation aircraft. Disseminated with publication.
2) A data processing method was developed to separate tones and broadband noise in wind tunnel experimental acoustic data for a CROR configuration, validated on multiple data sets. A method was developed and verified to assess the acoustic modes in the inlet of a UHBR with a sensor array, including guidelines for its design. Disseminated to Airbus.
3) A design approach for geometrically scaled liners in wind tunnel models was developed, taking into account performance requirements, manufacturing, and testing constraints, verified on eight samples. Disseminated with publication.
4) Wind tunnel experimental data in the DNW-LLF data base for the CROR configuration from Clean Sky 1 were extrapolated to higher Mach numbers for representativeness at aircraft take-off, validated with experimental data. Disseminated to Airbus
5) Design methods and advanced finite element modelling methods were developed to extend the aeroshape of the fan blade at wind tunnel scale to a full composite fan blade structure, including ply lay-up and orientation, for accurate manufacturing, verified on coupon and element levels, against the fan aeroshape from the EU ASPIRE project, and later applied for an UHBR wind tunnel test. Extended abstract submitted. Exploited in SAAFIR wind tunnel test.
6) Numerical methods were developed to represent both buzz saw noise (dominant sound source at take-off) and the behaviour of acoustic liners (to reduce engine noise) in the intakes of turbofans in CFD-based simulations. The method for acoustic liners was validated in a liner test facility. Realistic sounds were obtained when simulating buzz saw noise. The effectiveness of the acoustic liners in attenuating the buzz saw sound waves could be quantified. Extended abstract submitted.
7) A new generation of rotating balances was developed for force and moments measurements in wind tunnel models of engines, with additive manufacturing of a defect free topology-optimised balance demonstrator . Disseminated to Airbus and through social media.
8) A concept for a data acquisition system was developed for a large number of dynamic sensors (microphones and pressure sensors) in the limited space of a UHBR wind tunnel model, with a technology demonstrator with validated functionality. Disseminated to Airbus. Exploited in SAAFIR wind tunnel test; further exploitation foreseen in Clean Avation and for ZEROe.
9) Numerical methods were developed for mutual aero-acoustic interference between the UHBR engine and an airframe, including high lift. Analysis were carried out in cruise for aerodynamic effects and at take-off/sideline conditions for acoustic characteristics. Disseminated to Airbus.
10) A numerical method based on Large Eddy Simulations (LES) was developed to quantify the jet noise characteristics of UHBR engine, validated with several experimental cases. Disseminated to Airbus.

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)

Progress beyond state of the art and specific expected potential impact

Referring to the main results:
1) Take-off and approach acoustic characteristics of an aircraft are measured using ground instrumentation. In the NINHA EU project microphones were flush mounted on a A320 (chase aircraft) front fuselage to measure the noise coming from above (A400M). PropMat’s method with microphones mounted on a nose boom, not impacted by engine noise, enables meeting for the first time the much wider angular range required for Open-Rotor measurements.
2) The standard processing method for separation of tonal and broadband noise in wind tunnel experimental acoustic data of turbofans is not possible for CROR engines. PropMat provides the method to obtain this separation for understanding the noise-generation mechanism of CROR engines.
3) The scaling/tuning technologies developed for acoustic liners in wind tunnel models are a major step forward to wind tunnel testing with representative acoustic liners, which results in better prediction of the full scale acoustics.
4) The wind tunnel experimental database from Clean Sky1 could be extrapolated to a Mach number that could not have been tested.
5) For metallic fan blade design for wind tunnel models a steady-state shape pre-deformation correction is computed. PropMat has modelled light weight composite fan blades at wind tunnel scale more accurately towards the final target of accuracy.
6) The novel integration of acoustic liners in CFD computations allows to predict their contribution to community noise reduction, which could not be done. Combined with novel numerical representation of buzz saw noise, this is an essential enabler for industry to master (short-inlet) UHBR engines community and cabin noise during approach.
7) The novel manufacturing method for rotating balances allows for increased measurement accuracy, while reducing manufacturing cost and time, thus. enabling better predictions about the full scale next-generation engine design.
8) The demonstrated concept of the dynamic data acquisition system enables significantly more aerodynamic and aero-acoustic sensors to be used than presently. With the ever increasing needs for such measurements with advanced engines, this will be the dynamic data acquisition system for the next generation wind tunnel models.
9) A novelty in the numerical methods developed is that they enable computation of the acoustic characteristics of an installed engine.
10) The numerical methods allowed to compute far-field jet noise levels with known difference with experimental data.

Expected impact (overall)
Economic and environmental: PropMat’s innovations on numerical and experimental means are key steps to obtain a deep understanding of and to master the acoustic behaviour of innovative engines at all aircraft models (concept, wind tunnel model, flight test demonstrator, product aircraft). This reduces the development risk of emission-friendly aircraft with non-conventional acoustic behaviour.
Economic and socio-economic: PropMat enables a technology leap by the European industry in the face of emerging competitors for large passenger aircraft which are also investigating low-to-zero emission aircraft such as Open Fan, UHBR, and hydrogen burn concepts. With Clean Sky 2 and Clean Aviation, Europe takes the lead.

Validation of wind tunnel data processing method for separation of broadband and tonal noise

During the flight test of the innovative chase aircraft acoustic in-flight measurement method

Generic concept of PropMat DynDAS technology demonstrator

Master module of DynDAS demonstrator (on the left) with a single chain, consisting of two slave modu

Topology optimized rotating balance design developed at NLR

manufactured geometrically scaled liners for in-situ impedance testing in flow duct facility (scale

Extrapolation of DNW-LLF acoustic results to higher Mach numbers

Detailed analysis of propeller noise measured during flight test of PropMat’s innovative chase aircr

NLR's Citation research aircraft equipped with nose boom with acoustic sensors

Extrapolated pressure distribution from DNW-LLF wind tunnel test

Campbell diagram for fan blade external aeroshape, extended by PropMat with blade foot and internal

Verification of three candidate methods for acoustic mode detection (green) in the inlet of a UHBR a

Tensile test of element representative for composite fan blade with foot of a UHBR engine at wind tu

Finite element model of fan blade with foot in Abaqus

View from NLR’s Citation research aircraft on the propeller aircraft of which the noise is measured