Periodic Reporting for period 3 - SUBLIME (Supporting Understanding of Boundary Layer Ingesting Model Experiment)
Reporting period: 2021-12-01 to 2023-03-31
The introduction of boundary layer ingesting (BLI) propulsors integrated with the rear fuselage in large passenger aircraft poses new challenges regarding accurate assessments of the power savings potential over conventional podded installations.
The COVID-19 pandemic has accelerated the wish for zero emission air travel and so methods for reducing power requirements are more relevant now that when the project started
The project has allowed the beneficiaries maintain and increase their workforce, providing and maintaining high value employment throughout Europe, where the COVID-19 pandemic has seen job losses in the aerospace and wider industry, the clean sky2 programme as a whole has helped to safe guard employment.
The resulting combined experimental and CFD database of SUBLIME has allowed better understanding the dependencies among the propulsor shape, fan inlet distortion pattern and the corresponding power savings. The SUBLIME project has provided methodologies, tools and facilities & a modular/ re configurable wind tunnel model to the European aviation industry, therefore contributing to releasing the full potential of power saving of BLI engines.
The COVID-19 pandemic has accelerated the wish for zero emission air travel and so methods for reducing power requirements are more relevant now that when the project started
The project has allowed the beneficiaries maintain and increase their workforce, providing and maintaining high value employment throughout Europe, where the COVID-19 pandemic has seen job losses in the aerospace and wider industry, the clean sky2 programme as a whole has helped to safe guard employment.
The resulting combined experimental and CFD database of SUBLIME has allowed better understanding the dependencies among the propulsor shape, fan inlet distortion pattern and the corresponding power savings. The SUBLIME project has provided methodologies, tools and facilities & a modular/ re configurable wind tunnel model to the European aviation industry, therefore contributing to releasing the full potential of power saving of BLI engines.
The main Achievements include:
- All activities have been concluded and all deliverables submitted
- Combined Experimental - CFD database of two BLI configurations and a reference configuration
- Developed a modular wind tunnel model able to characterise rear fuselage propulsor geometries.
- Optimised propulsor geometries have been developed for wind tunnel scale configurations and full scale applications. The optimisation activity aimed to maximise the power saving of the BLI propulsor configurations
- Three rear fuselage configurations have been tested
- Two wind tunnel test campaigns measured rear fuselage loads, fuselage boundary layer development, surface pressures, AIP distortion and configuration wake characteristics using a traversing rake assembly.
- Generation of an Experimental database of 2 BLI configurations at transonic conditions.
- CFD database of the experimental configurations has been generated to allow validation of CFD & assessment of power saving potential
- Gas turbine performance maps with varyng levels of power off-take have been developed to guide overall aircraft level assessment of BLI configurations
- Fans have been designed that accept the distortion from the BLI360 & BLI180 configurations, with the efficiency understood
- Methodologies to measure the power saving of efficiency of boundary layer ingesting rear fuselages have been developed to help understand the potential improvements from ingesting the fuselage boundary layer
- All activities have been concluded and all deliverables submitted
- Combined Experimental - CFD database of two BLI configurations and a reference configuration
- Developed a modular wind tunnel model able to characterise rear fuselage propulsor geometries.
- Optimised propulsor geometries have been developed for wind tunnel scale configurations and full scale applications. The optimisation activity aimed to maximise the power saving of the BLI propulsor configurations
- Three rear fuselage configurations have been tested
- Two wind tunnel test campaigns measured rear fuselage loads, fuselage boundary layer development, surface pressures, AIP distortion and configuration wake characteristics using a traversing rake assembly.
- Generation of an Experimental database of 2 BLI configurations at transonic conditions.
- CFD database of the experimental configurations has been generated to allow validation of CFD & assessment of power saving potential
- Gas turbine performance maps with varyng levels of power off-take have been developed to guide overall aircraft level assessment of BLI configurations
- Fans have been designed that accept the distortion from the BLI360 & BLI180 configurations, with the efficiency understood
- Methodologies to measure the power saving of efficiency of boundary layer ingesting rear fuselages have been developed to help understand the potential improvements from ingesting the fuselage boundary layer
The SUBLIME projects progress beyond the state of the art:
#1: Developing understanding of sub-scale to full-scale scaling, similarities and performance metrics for integrated BLI configurations.
#2: Parametric DoE CFD design space exploration of high-speed BLI 360 configurations.
#3 Modular High-speed wind tunnel model for investigating installed BLI configurations.
#4: Advanced aircraft/propulsor coupling design for BLI
SUBLIME has advanced knowledge of BLI coupled aero-propulsive model that has improved understanding of BLI propulsion systems. The project has considered a large search space for dealing with integrated BLI propulsion systems. For the experimental campaigns a small portion of this design space was selected to investigate two BLI concepts and reference configuration carried out over a Mach range of 0.2 to 0.8 with advanced measurement techniques.
#5: Advanced manufacturing techniques:
The SUBLIME project has made extensive use of metalic 3D printed components for the the construction of the wind tunnel model and has included Titanium DLMS components for the propulsors and the WAAM process for the aluminium nose. This has furthered knowledge of these manufacturing techniques to produce intricate components that are subject to high pressures & the internal routing of pressure measuring runs
#6: Advanced measurement techniques
The ARA PIV system has been used to make off surface flow measurements ahead of the propulsor intake. The SUBLIME project has build on lessons learnt from the CS2 ANACO project to increase the robustness of a unique capability for non-intrusive measurements in an industrial wind tunnel. This data provide a high value rich dataset for increased understanding of the flow physics and CFD validation on BLI configurations.
#7: High-speed wind tunnel testing of BLI aircraft configurations
The SUBLIME project has provided opportunity to test integrated BLI aircraft configurations up to transonic cruise Mach. Transonic experimental tests of integrated powered BLI configurations have not previously been performed. This experimental database from the SUBLIME project is an ideal CFD validation source that will increase the confidence of future CFD based design studies. This will benefit the SUBLIME consortium and the company of the TM by learning from and exceed the knowledge gained from previous studies.
#8: Realistic fan simulation in BLI propulsors
In SUBLIME, appropriate CFD modelling for simulation of fan effects and nacelle/fan interactions has been undertaken using source terms which replicate the presence of fan blading at an appropriate level of accuracy suitable for reliable installed predictions (i.e. BFM). This will eventually make it possible to derive fan maps under distorted flow, i.e. pressure ratio and efficiency vs. corrected mass flow from choking to actual surge line.
#6: Advanced Hybrid Momentum-energy Based Assessment Techniques
Hybrid method based on a complimentary combination of momentum and energy conservation have been used in SUBLIME and takes advantage of a multi-physics based approach, which will allow for application to both experimental and CFD investigations. It brings with it more opportunities to establish improved links between experiment and CFD. The hybrid method enables greater insight into BLI physics and related flow mechanisms, which is embellished by the combination of experimental and CFD datasets.
#1: Developing understanding of sub-scale to full-scale scaling, similarities and performance metrics for integrated BLI configurations.
#2: Parametric DoE CFD design space exploration of high-speed BLI 360 configurations.
#3 Modular High-speed wind tunnel model for investigating installed BLI configurations.
#4: Advanced aircraft/propulsor coupling design for BLI
SUBLIME has advanced knowledge of BLI coupled aero-propulsive model that has improved understanding of BLI propulsion systems. The project has considered a large search space for dealing with integrated BLI propulsion systems. For the experimental campaigns a small portion of this design space was selected to investigate two BLI concepts and reference configuration carried out over a Mach range of 0.2 to 0.8 with advanced measurement techniques.
#5: Advanced manufacturing techniques:
The SUBLIME project has made extensive use of metalic 3D printed components for the the construction of the wind tunnel model and has included Titanium DLMS components for the propulsors and the WAAM process for the aluminium nose. This has furthered knowledge of these manufacturing techniques to produce intricate components that are subject to high pressures & the internal routing of pressure measuring runs
#6: Advanced measurement techniques
The ARA PIV system has been used to make off surface flow measurements ahead of the propulsor intake. The SUBLIME project has build on lessons learnt from the CS2 ANACO project to increase the robustness of a unique capability for non-intrusive measurements in an industrial wind tunnel. This data provide a high value rich dataset for increased understanding of the flow physics and CFD validation on BLI configurations.
#7: High-speed wind tunnel testing of BLI aircraft configurations
The SUBLIME project has provided opportunity to test integrated BLI aircraft configurations up to transonic cruise Mach. Transonic experimental tests of integrated powered BLI configurations have not previously been performed. This experimental database from the SUBLIME project is an ideal CFD validation source that will increase the confidence of future CFD based design studies. This will benefit the SUBLIME consortium and the company of the TM by learning from and exceed the knowledge gained from previous studies.
#8: Realistic fan simulation in BLI propulsors
In SUBLIME, appropriate CFD modelling for simulation of fan effects and nacelle/fan interactions has been undertaken using source terms which replicate the presence of fan blading at an appropriate level of accuracy suitable for reliable installed predictions (i.e. BFM). This will eventually make it possible to derive fan maps under distorted flow, i.e. pressure ratio and efficiency vs. corrected mass flow from choking to actual surge line.
#6: Advanced Hybrid Momentum-energy Based Assessment Techniques
Hybrid method based on a complimentary combination of momentum and energy conservation have been used in SUBLIME and takes advantage of a multi-physics based approach, which will allow for application to both experimental and CFD investigations. It brings with it more opportunities to establish improved links between experiment and CFD. The hybrid method enables greater insight into BLI physics and related flow mechanisms, which is embellished by the combination of experimental and CFD datasets.