Integrated Duct Aerodynamics

Purpose and goal

Various CFD methods for analysis of integrated compressor ducts were evaluated. A duct designed by GKN for the rig ENYA has been tested and the results have been used for validation within IDA. A proposed methodology using DDES for verification analysis has been suggested for further development. The effect of bleed rate on the flow in the compressor duct has been identified and the risk of boundary layer separation in the duct during operation at part-speed has been assessed. The benefits of a fully integrated design concept have not been assessed.

Expected results and effects

Chalmers has developed a methodology for numerical analysis of integrated compressor ducts. DDES has been proposed as a balanced compromise between accuracy and speed. The DDES model has been implemented in the code G3D::FLOW and was evaluated on parts of the test rig ENYA at GKN. DDES analysis with G3D::FLOW is too time-consuming to compete with RANS (state-of-the-art). The risk of separation in the duct during part-speed operation with high bleed rates has been assessed based on CFD results from RANS.

Planned approach and implementation

The planned collaboration with Loughborough University on testing for validation of CFD did not happen during the IDA project. Instead, test data from the GKN rig ENYA was successfully used. In 2017, Chalmers and Loughborough applied for and were granted a joint CfP (Call for Proposals) project within Clean Sky 2 WP6 focused on integrated compressor ducts. Development of the DDES model in G3D::FLOW was more time-consuming than planned and combined with long analysis times this resulted in failure to achieve the objective to evaluate a complete integrated compressor duct with DDES.