Lightweight aircraft engines of the future

ICD stands for Inter Compressor Duct and is the name of the transition channel between the low- and high-pressure compressors. The aim is to better tailor the low-pressure compressor, ICD and high-pressure compressor to each other, in order to identify and exploit the potential for new engines that save even more fuel. One important step on this path is the systematic measurement of flow conditions in short, sharply angled ICDs. To this end, a completely new wind-tunnel test rig has been constructed at the DLR Institute of Propulsion Technology in Cologne – the MTU Center of Competence for Propulsion Systems.

Test operations were started in the presence of representatives of the three partners – DLR, MTU and GKN Aerospace Engine Systems. "As a national research centre, DLR plays a key role in the progressive development of the entire air transport system," said Rolf Henke, Member of the DLR Executive Board responsible for aeronautics research. "There have been great advances in propulsion in recent decades. Together with our partners MTU and GKN, we are very proud to introduce a further large step with this ICD rig."

For MTU, which is leading the development of the system, Dr Gerhard Ebenhoch, Director Technology Management, explained: "In this collaboration, the strengths of the partners are outstandingly integrated – the skills of GKN in large, static components; the experience of DLR in the field of testing; and the compressor and system competence of MTU."

For GKN Aerospace Engine Systems Robert Lundberg said: “To be able to validate our technologies at high TRL in a unique rig is really an opportunity for GKN. We have no chance to do this by ourselves in Sweden, so it really shows the importance of European collaboration.”

For Clean Sky the Project Officer of the Engine-ITD Jean-Francois Brouckaert acknowledged: "This new test facility allows us to perform important EU collaborative research on the next generation of engines. Congratulations to the MTU, DLR and GKN team for achieving this important milestone! It is an excellent example of complementarity between experimental and numerical work."

Measurement technology at the highest level of detail

The ICD rig measures the channel flow in unprecedented detail: 500 pressure measurement points, probe measurements at three traversal levels, and laser techniques and turbulence probes allow an accurate insight into the flow. Dr. Gerhard Kahl, Chief Engineer, Technology Demonstrators and Rigs at MTU is certain: "With these tests, we will significantly advance our understanding of the flow in the ICD, in order to further reduce the overall length, and thus the weight of the engines, with particularly compact designs."

The work is ongoing – over the course of the next year, three different ICD configurations will be tested. Building on the results achieved, a two-shaft test rig is to be designed in 2019 and constructed in the following year. The aim is for low- and high-pressure compressors to be tested together from 2021.

DLR in engine research

DLR is the national aerospace research centre of the Federal Republic of Germany. Experimental and numerical methods for future aircraft engines are developed in the aircraft propulsion field. The aim is to reduce noise and emissions through improved turbomachinery components and their intelligent interaction. DLR has an interdisciplinary approach to this work and is investigating new compressor-, combustion-chamber- and turbine-designs on unique large-scale test rigs. In addition, DLR is exploring the opportunities for the intelligent integration of new types of propulsion in future aircraft. DLR is developing solutions for the engine technologies of tomorrow in cooperation with partners from the fields of science and industry. DLR is a core partner in the Clean Sky 2 programme and works together with European engine manufacturers on the implementation of large technology demonstrators.