Fraunhofer Institute for Production Technology IPTResearch project "HyAMAPU"
Climate change and global warming are major challenges facing society. Hydrogen (H2) will play an important role as an energy source because hydrogen combustion does not produce carbon dioxide (CO2). However, it produces more nitrogen oxides (NOx) than the combustion of fossil fuels. For this reason, the hydrogen combustion process needs to be redesigned to produce less NOx, and rapidly deployable solutions are required.
The aim of the joint project "HyAMAPU - Investigation of an Integrated Process Chain for the Production of a Micromix Combustion Chamber" is to develop a "plug and play" combustion chamber that can be retrofitted into existing auxiliary power units (APU) for 100% hydrogen combustion.
MicroMix: Lower NOx emissions thanks to many small flames
The hydrogen combustion chamber developed by project partner FH Aachen features the patented MicroMix (MMX) design. Compared to conventional combustion processes with several large flames, it uses many small flames, an innovation that reduces nitrogen oxide emissions to the level of fossil fuel combustion.
The MMX combustion chamber is designed to optimize gas flow with virtually no dead water areas. The external geometry also supports the flow behavior of the flame rings. The additive manufacturing of such a prototype MMX combustion chamber has already been successfully tested in an internal project.
Production chain combines additive and subtractive processes
To manufacture the MMX combustion chamber, the project team uses the laser powder bed fusion (LPBF) process. With LPBF, the combustion chamber can be manufactured as an integral component with all functional elements, such as the air baffles, already fully aligned. In addition, the LPBF process significantly reduces the time and effort required to drill the spoke centering holes.
After the combustion chamber is additively manufactured and the platform on which it is built separated from the building plate, the component is further processed: For example, the delicate moving air baffles and the holes for the hydrogen outlet are machined.
50 percent less NOx emissions
A key goal of the project is to reduce NOx emissions while keeping CO2 emissions at a constant 0 percent. At the end of the project, NOx emissions will be reduced by more than 50 percent compared to Jet A1 combustion.
50 percent reduction in production time and cost
Economic efficiency is not neglected either. Another goal of the project is to reduce production times and costs. The goal is to achieve at least the same environmental footprint while reducing production time and costs by 50 percent.
A comprehensive quality assurance concept for the additively manufactured MMX combustion chamber will be developed in order to prepare the qualification of the manufacturing process chain according to aerospace standards and thus to disseminate the H2 technology.
Project partners
- Präwest Precision Workshops Dr.-lng. Heinz-Rudolf Jung GmbH & Co. KG, Bremen (coordination)
- Fraunhofer IPT, Aachen
- FH Aachen, Aachen
- Diehl Aerospace GmbH, Überlingen
- Oetzbach Edelstahl GmbH, Velbert
- TPW CTinspect GmbH, Neuss
Associated partner
Honeywell Aerospace, Prague 11-Chodov, Czech Republic
Funding
The project "HyAMAPU - Investigation of an Integrated Process Chain for the Production of a Micromix Combustion Chamber" is funded by the German Federal Ministry of Economics and Climate Protection.
Project management organization: DLR Project Management Agency for Aviation Research
Funding reference: 20M2214E