Windtunnel tests have begun in Germany as part of a project seeking to improve engine compressor efficiency in an effort to reduce the weight of future powerplants.

Munich-based engine specialist MTU is leading the effort, which also involves UK engineering firm GKN’s Sweden-based Aerospace Engine Systems division – the former Volvo Aero business – and German aerospace research centre DLR.

A special test rig has been constructed at DLR’s windtunnel facility in Cologne to assess the airflow in the inter-compressor duct (ICD) between the low-pressure (LP) and high-pressure (HP) compressors.

MTU says the objective is to "precisely fine-tune" the interaction between the two compressors and ICD, and to "identify and leverage" potential efficiencies in order to build a shorter, more lightweight engine.

Part of the effort will concentrate on "systematic mapping" of flow conditions in "short, steep transition channel [ICDs]", MTU says.

It adds the test rig will provide an "unprecedented depth of detail" about the flow conditions by using "500 pressure tapping points, probe measurements at three traversal levels… laser technology and turbulence probes".

MTU chief engineer for technology demonstrators and rigs Gerhard Kahl states that the aim is to come up with "particularly compact [compressor] designs".

The team plans to test three different ICD configurations in 2018 and, based on the findings, design a two-shaft test rig in 2019. Tests of combined LP and HP compressors are scheduled to begin in 2021.

MTU says that the results of the tests "could already go into the next generation of geared turbofan engines". The manufacturer is a partner in Pratt & Whitney’s PW1000G geared turbofan programme, and supplies the LP turbine and part of the HP compressor for that engine family.

GKN and DLR are long-term partners, MTU notes. It says GKN is contributing know-how in large static components to the project, while DLR has been recruited for its testing experience.

The project is part of the EU's Clean Sky future technology research programme.

Robert Lundberg, director European research & technology programmes at GKN's Swedish aerospace division, says: "To be able to validate our technologies at a high TRL [technology readiness level] in a unique rig is really an opportunity for GKN. We have no chance to do this in Sweden, so it really shows the importance of European collaboration."