FLOW Control Actuators at Aircraft scale manufacturing by SLM with high aerodynamic performance for using in Harsh environment

Project Information

FLOWCAASH

Grant agreement ID: 785408

DOI

10.3030/785408

Project closed

EC signature date 24 January 2018

Start date 1 April 2018

End date 31 December 2020

Funded under

• SOCIETAL CHALLENGES - Smart, Green And Integrated Transport

Total cost

€ 549 061,25

EU contribution

€ 549 061,25

Coordinated by

LORTEK S COOP
Spain

Periodic Reporting for period 2 - FLOWCAASH (FLOW Control Actuators at Aircraft scale manufacturing by SLM with high aerodynamic performance for using in Harsh environment)

Reporting period: 2019-04-01 to 2020-12-31

Summary of the context and overall objectives of the project

The aerospace industry needs a more ecological and economic engine. Ultra High Bypass Ratio (UHBR) are optimized engines with lower CO2 and NOx emissions, higher efficiency and lower fuel consumption. However, their integration brings new challenges to overcome. The use of Active Flow Control (AFC) can suppress the problems, so actuators need to be installed in restricted spaces and with complex geometry. Selective Laser Melting (SLM) emerges as a potential manufacturing process since it allows complex and unique product geometries which minimise product cost and weight, and produces minimal waste. In addition, the SLM manufacturing method enables component designs consisting on few single parts, reducing the risk of leakage and thus, increasing the reliability of the AFC system during flight operation.

The main goal of FLOWCAASH was to design and manufacture reliable and safe flow control actuators for aircraft by SLM able to withstand the high temperatures and pressures during flight test, aerodynamic performance and high resistance to harsh environments including rain, icing, sand and dust, vibrations and anti-icing fluid. Pulsed Jet Actuators (PJA) and Steady Blowing Actuators (SBA) have been designed, manufactured and tested.

The main conclusions are the following:
• The design of SBA and PJA actuators has been optimized to be printable by SLM.
• Cracks have been avoided and distortions have been minimized by modifying the design and optimizing the supporting strategy.
• Distortions have been predicted by numerical modelling simulation. Simulation results were used to optimize the design, the orientation and supporting strategy.
• It was demonstrated that the SLM process is stable and reproducible. The quality of the manufactured actuators is consistent, the quality of the powder is maintained without being degraded in at least 9 manufacturing cycles, and density and mechanical properties are constant within the different manufacturing processes.
• SBA actuators have been fully characterized by aerodynamic and harsh environment tests and showed an adequate performance.
• The design of the channels of PJA actuator needs to be optimized for an adequate aerodynamic behavior, but it is good if two holes are performed in the channels.

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 designs of SBA and PJA were optimized based on the distortion prediction simulation results and dimensional measurements, which led to minimized dimensional deviations. Design rules were determined for Ti6Al4V and SLM technology and were implemented in the designs. Ti6Al4V powder was characterized to verify its usefulness for SLM process. Processing parameters were optimized to guarantee a defect free material. Two iterations of SBA and PJA actuators were manufactured by SLM, post-processed and tested. Different test benches were developed and adapted for aerodynamic and harsh environment testing. Reproducibility verification was also assessed to demonstrate that the SLM process was stable and repeatable. The recycled powder was analysed concluding that the powder properties are not degraded significantly.

The following main results can be highlighted:
• SBA and PJA actuators have been successfully manufactured by SLM. The design was developed for each actuator taking into account design guidelines and distortion prediction simulations to be printable by this technology.
• For PJA actuator, the geometry of the feedback channels should be modified to avoid performing holes in these channels.
• Powder was effectively removed from PJA actuator channels using sophisticated depowdering systems.
• SBA actuators show a good aerodynamic behaviour and high resistance to harsh environments. The designs are sufficiently robust to avoid structural damage.
• PJA actuators are more susceptible to minimum design variation. One PJA actuator has a good aerodynamic behaviour and all showed resistance to harsh environments.
• The SLM process is reproducible and the quality of the actuators is also stable.

Several activities were performed to disseminate the project to a wide audience, including industry, scientists, academia and public bodies. 3 key results were identified for exploitation.

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)

Innovative and complex designs of Flow Control Actuators, not feasible to manufacture by conventional technologies, have been developed and manufactured by SLM. It was demonstrated that the developed actuators have a high aerodynamic behaviour and they assure a safe operation under harsh environment conditions.
The progress beyond the state of the art is:

ACTUATORS’ OPTIMAL DESIGN FOR AM
- Development of new designs of flow control actuators to be used in UHBR engines.
- Distortion prediction simulations to know beforehand the behavior of the new actuators design before manufacturing by SLM, avoiding trial-and-error manufacturing for a cost-saving process.
- Definition of Ti6Al4V design rules for the minimum number of supports meeting dimensional requirements
- Multifunctional configuration in terms of dissimilar stiffness at different locations of the parts.

SLM PROCESS OPTIMIZATION
- Use of advanced SLM strategies to improve structural strength up to 260°C
- Optimization of the supporting strategy and the orientation of the actuators to be printable by SLM.
- Simulation to predict distortions and avoid them in the manufacturing of Ti6Al4V parts.
- Consideration of the whole value chain of additive manufacturing (powder properties, design, SLM process, metallurgy, post-processing, mechanical properties, and distortion simulation) to make the process repetitive.

NEW MATERIAL PERFORMANCE WITH REGARD TO AERODYNAMIC AND HARSH ENVIRONMENT TESTS
- A deeper knowledge on properties regarding aerodynamic and harsh environment behaviour of parts manufactured by SLM in aerospace application
- The obtained results have been used to optimize the designs to assure a safe operation under harsh environment conditions.

The main outcomes of the project are:
-Development of new Flow Control Actuators concepts by SLM based on lightweight and downsizing designs suitable for UHBR engines
-Definition of design guidelines for Ti6Al4V alloy processed by SLM
-Increased knowledge about SLM manufacturing criteria for titanium large parts
-Deeper knowledge in distortion prediction numerical models
-Deeper knowledge on how the physical characteristics of the actuators manufactured with SLM process determine the results obtained in the aerodynamic and harsh environment test, under different stresses applied
-For aerodynamics tests, it is possible to evaluate the repeatability and steadiness of the SLM process.
-For harsh environment tests (rain, icing, sand & dust, vibration and anti-icing fluid), the performance of the SLM process under different stresses applied has been assessed.

Economic impact: The more efficient UHBR engines will reduce fuel consumption bringing economic benefits.

Technological impact: It was demonstrated the possibility to manufacture Ti6Al4V parts with intricate design and channel structure not feasible up to day by SLM.

Industrial impact: Optimization of design and manufacturing of complex and unique product geometries is a key factor for European aircraft industry competitiveness.

Environmental impact: Contribution for the development and implementation of UHBR propulsion systems that lead to a reduction of CO2 , NOx and noise emissions.

Social and Other impact: promotion of jobs on the manufacturing ecosystem.

Heat treated and sand blasted PJA actuator manufactured by SLM

Heat treated and sand blasted SBA actuator manufactured by SLM

Distortion prediction simulation of PJA actuator