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A New proTection devIce for FOD

Periodic Reporting for period 3 - ANTIFOD (A New proTection devIce for FOD)

Reporting period: 2020-11-01 to 2022-01-31

The Electrical Environment Control System (eECS) takes external fresh air from an inlet. Depending on aircraft altitude and type of inlet, debris and contaminants may be ingested and cause premature degradation of pack performances, affecting the cabin air quality and reducing eECS components' lifetime. The project has allowed the development of a novel protective solution to prevent eECS performance degradation due to FOD.

In this sense, the ANTIFOD project is well aligned with Clean Sky 2 which aims to achieve up to a 30% reduction in fuel burn and related CO2 emissions; similar or greater reductions in NOx emissions and to drive the European aviation industry to be commercially competitive in a 30 years period (from 2020-2050).

The main objective of this innovation action has been to develop a Foreign Object Debris (FOD) protection device applied to an electrical ECS fresh air inlet, validated to TRL5. This has been achieved through the following two-stage design process, each with its own secondary objectives:

1. Preliminary design, which has aimed to:
- Capture the top-level requirements, used to develop a set of baseline candidate concepts.
- Use innovative design methods to conduct a concept study.
- Verify prototypes rapidly using a combination of CFD and additive manufacturing comparing calculated separation efficiency and pressure loss.
- Refine the highly ranked concepts via a trade-off study and determine the best-suited solution that meets all the top-level requirements.
- Produce a preliminary design from the winning concept, including feasibility study, sensitivity analysis, risk assessment, and system requirements report, measured through a preliminary design review (PDR) which demonstrates compliance with the user needs.

2. Detailed design, which has aimed to:
- Define an aerodynamic geometry for the intake protection and FOD separation device which demonstrably meets the relevant requirements and integrates with the mechanical interfaces of the
existing intake scoop inlet, scoop ducting and eECS inlets, and is measured through Wall-Modelled LES simulations.
- Produce a detailed design and subsequent manufacture of the full-scale intake protection and FOD separation device.
- Design a test bench to validate the intake protection and FOD separation device
- Deliver two final full-scale working prototypes to the Topic Leader capable to accomplish the project requirements on FOD separation efficiency and pressure drop.
The work performed during the first period of the project has been focused on:

1. Identification of the Top Level Requirements for the design of the FOD protection device:
- Identify and characterize FOD developing test samples according to FOD specifications.
- Characterize aerodynamic conditions at aircraft air inlet depending on inlet type and position as well as aircraft environment.
- Specify the efficiency breakdown for each item to reach the overall efficiency with the support of the Topic Leader.

2. Trade and selection of the appropriate ANTIFOD system:
- Generation of a baseline for candidate concepts.
- Process for FOD separator development (Design phase, trade-off, verification by tests).


The work performed during the second period of the project has been focused on:

- Select a final intake geometry.
- Determine the criteria selection weighting from the Top Level Requirements.
- Optimize a FOD separator candidate iterating between low order code and CFD analysis.
- Optimize an intake protection device geometry.
- Prepare the strategic plan for the experimental test bench procedure on both the FOD separation efficiency device test and the whole system device test.

The work performed during the last period has not only allowed a novel FOD protection device has been designed, prototyped and tested but also some
other exploitation and dissemination of results are available through:

- 3 different experimental setups for separation efficiency, pressure drop and detailed fluid dynamic analysis.
- 2 different numerical simulation tools (low order code and CFD codes) for optimization separation efficiency analysis.
- Academical 2,5D FOD experimental setup together with the different numerical tools for detailed phenomenological analysis.
From a technical and scientific point of view different ambitious concepts which implies progress beyond the state of the art can be detailed as:

1. More realistic simulations of particle trajectories in detached turbulence areas, at feasible cost and time.
2. More realistic test dust for more accurate prediction of engine life and cost-of-ownership of IPS and related particle separators based on the potential of unseparated particulate to cause damage, thanks to full chemical characterization of unseparated particulate using more realistic sand and dust for separation efficiency measurements.
3. Improvement of the actual bulk gravimetric separation efficiency by means of the development of a new metric to assess IPS efficiency through a new cost function for optimization of IPS systems.
4. Multiple measurement techniques (PIV, PSP and/or hot wire) for duct flow characterization across FOD separator instead of actual characterization based on total pressure rakes or PIV.
5. Use of narrow size fraction material to fully understand the behaviour of the separation through a range of particle sizes.

The main expected result until the end of the project has aimed at the development of a successful protection and separation device to remove a target FOD size with the minimum pressure loss.

From an industrial point of view the potential industrial impact is expected on:
1. Establishment of a clear methodology for the design of this kind of device. This will enable to reduce the time and the effort dedicated to the design of similar devices in the future.
2. Increase the expertise on FOD protection devices for electrical compressors within the European industry.
3. The new FOD concept developed enables the safe implementation of e-ECS, a critical system for the consolidation of more electrical aircraft.

The quantified safety impact of the project can be summarized as accomplishing all separation efficiencies expected with efficiency 3% higher than the requirement on FOD type 1, and 10% higher on FOD type 3.

In order to keep an adequate eECS performance to achieve the environmental impact (fuel consumption reduction), the pressure of the separation elements has been achieved also the expected threshold (4% lower pressure drop than initially required).

As commented, this project is a necessary step toward the safe operation of the eECS and also towards More Electrical Aircrafts (MEA) technologies and All Electrical Aircraft (AEA) systems, contributing to making aircraft more environmentally sustainable and more commercially competitive because of:
- Improved fuel consumption, due to a more efficient secondary power management.
- Reduced maintenance costs due to the elimination of the maintenance-intensive bleed system.
- Improved reliability due to the use of power electronics and lesser components in the engine installation.
- Expanded range, and reduced fuel consumption due to the reduction of weight.
- Reduced maintenance cost and improved reliability due to the reduction of components.

The final expected environmental impact of no-bleed aircraft in comparison with aircraft with motor bleed can be estimated in saving of fuels and emissions up to 5%.
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