The accurate modelling of a representative turbulence in an aero-engine fan stage is still a huge challenge in all current industry-based design methods. TurboNoiseBB will provide for the first time a step further into the integration of the higher accuracy CFD/CAA methods aforementioned into the multi-disciplinary fan-stage design. Comparisons with the experimental database, acquired using advanced aero-acoustics measurement techniques on the large scale UHBR fan stage (Anecom rig), will highlight the added value of the high fidelity CFD/CAA methods relative to industry RANS-based methods. Experimental results from parametric studies of fan/stator spacing, which shows significant difference in noise and flow behaviour will also be accurately captured through large scale testing at Anecom and will strengthen the quality of the database across the whole of the UHBR fan stage design space.
The final achievements of the project are
1) The unpreceded BBN fan test was completely conducted and delivered an enormous amount of precious measurement data.
2) All measurement data were documented and the test conditions well described. The database was distributed to all partners, who needed them for their further activities in the project.
3) The data analysis and appraisal were completed. In the frame of this, a substantial amount of information has been analyzed. The appraisal provided the certainty that the data sets are of maximum value, quality and completeness.
4) The acquired data sets establish a data-base, which did not exist before. It is unique in the world in its richness, quality and depth of information.
5) Various numerical predictions based on the reference fan geometry were undertaken.
6) The numerical results of four different numerical simulation methods (analytical, (U)RANS, stochastical turbulence based and scale-resolving) and combinations with acoustic prediction schemes were achieved and could be compared respectively with the experimental outcome of the fan tests.
7) Two benchmarks dealing with the impact of 1) turbulence model in RANS simulations and 2) acoustic analytical models in RANS-informed analytical prediction were organized. Over 10 partners were involved in this activity.
8) A design of a classical, aerodynamically optimized OGV is available from WP5, being further optimized acoustically both in terms of tonal as well as on BB noise.
9) The design of a novel, serrated, acoustically optimized OGV set has been completed in WP6. Its aeroacoustic BBN reduction potential has been thoroughly investigated by means of high-fidelity CFD and CAA simulation work.
10) Airbus performed a final assessment of the turbine predictions at aircraft level
10a) A sensitivity study shows that LR aircraft noise level is sensitive (more than 0.1EPNdB variation) to turbine broadband noise prediction uncertainty, when the turbine broadband noise is 2dB over predicted
10b) The TurboNoiseBB project allowed to improve the turbine acoustic prediction methods successfully within this 2dB overprediction limit.
11) Airbus performed a final assessment of the low noise OGV designs at aircraft level
11a) The OGV design showed a significant reduction of fan tonal noise but an increase of broadband noise, which led to no reduction of noise at aircraft level at approach and cutback.
11b) The serrated OGV design showed a promising reduction of EPNL at approach up to 0.7dB assuming the same reduction on the forward broadband
