ELSAA - Efficient Large-Scale Aerodynamic Analysis

Important results from the project

Different CFD methods have been applied for analysis of integrated systems. A compressor duct was designed and tested by GKN as part of a previous project (NFFP6 IDA), which was used to assess the validity of the different methods. A hybrid model is suggested for detailed analysis of integrated systems with bleed flow. The risk for separation in the duct and neighboring compressor blades have been identified. Simulations including neighboring components are needed to assess the impact of flow separations on the system.

Expected long term effects

A methodology has been developed at Chalmers for numerical analysis of integrated compressor ducts. A hybrid RANS/LES model has been implemented in the code G3D::Flow and was evaluated on parts of the test rig ENYA at GKN. Furthermore, a hybrid model in the code ANSYS CFX was used. Despite improvements done to the code to reduce computational time, the hybrid model is still too time-consuming to compete with RANS (current state-of-the-art) for design. Hybrid models should rather be used in a late stage of the design process, when a selected design is investigated in more detail.

Approach and implementation

At the beginning of the current project, the hybrid model implemented in G3D::Flow as part of the previous NFFP project IDA was highly time-consuming, with an expected analysis time of 2 years for a single operation point of an integrated system. Improvements done as part of the ELSAA project reduced this computational time to weeks rather than years. Collaboration with Loughborough University (LU) within Clean Sky 2 was performed in parallel to the ELSAA project, where method development and validation could be done on a different geometry which benefited both projects.