At a time when the aeronautical industry is investing about 70% of Research and Technology spending on making air transport increasingly environmentally-friendly, the next generation of engines will be giving off far more heat than their current counterparts. One of the challenges will be to optimize management of these rising heat levels, by drawing heat off from where it is generated, reusing as much as possible and dissipating the rest. AManECO project is aligned with the development of heat recovery solutions using very high-efficiency heat exchangers, with innovative designs and manufacturing methods such as metal additive manufacturing (AM) and experimental testing. These future generation of heat exchangers will supplement the actual HX designs, traditionally manufactured for oil equipment products, and will enable aircraft engines manufacturer´s, like SAFRAN, to strengthen its position as world leader in this type of complex parts.
AManECO created a new concept of HX after discovering the real limits of the metal AM, and in particular laser powder bed fusion technology (PBF-LB), in terms of thins geometries manufactured with INCO718 and AlSi7Mg0.6 alloys. As a result of the project, AManECO proposes a methodology to create a HX design in accordance with ECO-Design TA in CS2.
AM has a great potential in terms of parts design and optimization in the field of aero-engines, in particular for advanced gear turbofans and highly efficient engines where an increased amount of energy has to be dissipated in cooling fluids. In this project the target are heat exchangers and heat recovery systems optimization through the investigation of advanced AM techniques and tools to overcome the gap that still exists between these structures optimized at computer scale and the industrial reality, related to the lack of fundamental knowledge of AM limits in terms of microstructures, surface quality, geometrical accuracy, thin features and associated performances.
The work proposed in AManECO aims at optimizing the PBF-LB manufacturing process of HX on several points:
- Allowing to assess the potential of PBF-LB to design and build parts with radically new architecture, based on the knowledge to be developed and considering the Eco-design aspects.
- Allowing to optimize the conception phase of heat exchangers reducing the development time/cost/energy by assessing the limits of LPB-LB technology, in terms of wall thickness, holes/gaps, overhang angle, thin layers, surface finish, etc., and include these limits in the design tools.
- Allowing an optimization of material used (AlSi7Mg0.6 and INCO718) for the same efficiency, by finding for instance the optimal wall thickness in heat exchangers or new shapes with improved heat transfer capacity.
AManECO enhanced knowledge of metal AM and, specifically, the capability of PBF-LB process to manufacture thin layers and wall thickness with adequate surface finish using AlSi7Mg0.6 and INCO 718 materials. In particular, investigating aerothermal and mechanical performance of thin walls to predict them in the design of HX and be able to optimize the HX´s design process in an Eco-friendly way after knowing the limits of the metal AM technology.
All in all, the main benefit of AMANECO project has been to prove the suitable behaviour in terms of aerothermal and mechanical properties of heat exchangers made by additive manufacturing with innovative designs, taken advantage of the PBF-LB technology characteristics to manufacture almost 50% thinner wall thickness with AlSi7Mg0.6 and INCO 718 materials than the current state of the art and the application of novel customized surface treatments to HX´s internal channel which allows a better aerothermal performance. In addition, the time-to-market was reduced and the efficiency of the heat exchangers increased in comparison with conventional heat exchangers.
