Engine Integration on Transport Aircraft - The European Research Activities on Propulsion Airframe Integration

Kurzfassung

Environmental demands and the need to lower DOCs force industry to reduce fuel consumption and the noise emission of the aircrafts, which lead to an installation of engines with high bypass ratio. The main objective of this paper is to present the key results of a detailed study of the numerical prediction of thrust and drag on a Airbus-type transport aircraft configuration obtained within the EU-project AIRDATA. These research activities aim to accurately predict the installation drag for engines with different bypass ratios and at different flow conditions using structured as well as unstructured / hybrid approaches of today's state-of-the-art Navier-Stokes solvers. Results of installation drag predictions on the Airbus-type ALVAST configuration with powered engines of different bypass ratios will be analyzed for different flow and thrust conditions and compared with measurements. It is demonstrated, that numerical methods are able to predict installation drag within good accuracy when the non-physical spurious drag caused by approximation and discretization errors is separated. The paper will make use of different methods for spurious drag separation, such as force extrapolation to zero mesh size and spurious drag evaluation. The increasing complexity of the configurations turns structured mesh generation into a very complex, time and labour consuming process. Within this paper the capability of hybrid methods in combination with appropriate mesh adaptation techniques for accurate prediction of installation drag will be demonstrated. These investigations are performed at DLR on the DLR-F6 civil transport aircraft configuration. The results clearly show, that hybrid Navier-Stokes methods are capable to predict the installation drag with a good accuracy.