Higher efficiency and lower emissions: Two key goals for global aviation

Experienced Partners Bridge the Gap Between Development and Series Production

For more than 15 years, Fraunhofer IPT has been supporting its partners in the aviation industry in the development of new and increasingly efficient manufacturing processes for propulsion systems and aircraft components.

With the Production Launch Center Aviation (PLCA) at the research airfield Würselen-Aachen (formerly Aachen-Merzbrück), the gap between the development of new components and series production is now being closed: Our expertise in machining high-performance materials, digitization, and the optimization of complex production processes, as well as the scaling of automated process chains for series production, is brought together at the Aachen site with our research and industry partners. In this collaboration, the PLCA will grow into a state-of-the-art technology park in the coming years, closely connected to both the Aachen academic and research landscape and the aviation industry's manufacturing sector.

Sustainable Support from the Federal Government and the State of North Rhine-Westphalia

With the Production Launch Center Aviation, the first project for sustainable aviation is now being launched through structural strengthening funds for the Rhineland region. The federal government and the state further support the sustainable transformation of the Rhineland region with more than 14,8 billion euros. The state complements the federal funding with its own budgetary resources. To date, a total of 174 projects have been approved with a funding volume of around 1,52 billion euros.

New Strategies for Prototype Manufacturing

The team at Fraunhofer IPT's prototype manufacturing department produced a blisk with a diameter of around 650 millimeters and a blade length of approximately 250 millimeters from a single raw piece in March 2022. The component was a scale-model fan blisk made of Ti6Al4V, a particularly difficult-to-machine titanium alloy.

The blisk was designed by the German Aerospace Center (DLR) to be used, in collaboration with the Institute of Aircraft Propulsion and Fluid Machinery at the Technical University of Braunschweig and Rolls-Royce Germany, for testing on the crosswind test stand for aviation propulsion systems in Braunschweig.

"First Part Right"-Strategy for Manufacturing the Blisk Prototype

To avoid vibrations in the long fan blades during the milling process, the researchers had to determine optimal spindle speeds, especially for surface finishing. They continuously measured the workpiece dynamics, which changed throughout the milling process. The team used both reference measurements with a laser vibrometer and simulations based on the Finite Element Method (FEM). A self-developed software, which works based on the natural frequencies of the tool and workpiece, was used to automatically select the appropriate spindle speeds.

Funding Acknowledgment

The research project was funded by the state of Lower Saxony as part of the ERDF program.

Additive Manufactured Hydrogen Combustion Chamber in MicroMix Design

In an internal research project, FH Aachen, Fraunhofer IPT, and Präwest GmbH produced a prototype of an additively manufactured hydrogen combustion chamber. The special feature is the design of the combustion chamber: The patented MicroMix process uses many small flames instead of a few large flames, as in conventional combustion processes. This significantly reduces the emission of nitrogen oxides (NOx) to levels comparable to fossil combustion.

MicroMix: Reduced NOx Emissions Due to Many Small Flames

The hydrogen combustion chamber features the patented MicroMix design. Compared to conventional combustion processes with a few large flames, it uses many small flames. This reduces the emission of nitrogen oxides to levels comparable to fossil combustion. The MMX combustion chamber is designed to allow optimal gas flow, with almost no stagnant water areas. The outer geometry further supports the flow behavior of the flame rings.

Costs Reduced by Up to 90 Percent

In the joint research project, the partners use Laser Powder Bed Fusion (LPBF), an additive manufacturing process, to produce the combustion chamber. With LPBF, the combustion chamber can be made as a single integral component, with all functional elements, such as the air guide vanes, already perfectly aligned. Additionally, the effort required for the subsequent drilling of the nozzle center is significantly reduced in LPBF manufacturing.

Simulations have shown that the use of LPBF can reduce the costs and assembly time of such a combustion chamber by up to 90 percent.