| Summary: | Structures of an aircraft engine are not completely rigid. Therefore when they are subjected to aerodynamic loading, those structures will deform elastically and their shape will change, especially fan blades because of their size. Those elastic deformations and change in load can, depending on structural and flow characteristics, lead to stability problems and cause an excessive fatigue of the structure decreasing its lifetime or in the worst case, break the structure. Consequently it is necessary to study the engine response to aerodynamic loads to design it to prevent those problems and to simplify the certification. A way to do it is to use Computational Fluid Dynamics (CFD) calculations to predict behaviors and better explain phenomena. Today, the trend for turbofans in order to decrease their fuel consumption is to increase their bypass ratio so their fan diameter as well and consequently increase potential elastic deformations, and to shorten the length of the engine air intake to decrease the engine mass but therefore the flow homogeneity also. In these conditions, the crosswind has an increasing impact on turbofan engines because it can create instabilities on the fan blades. Therefore it is important to develop a method to predict the fan behavior under crosswind with a numerical simulation. The present study thus aims to develop a robust and accurate methodology which from a given crosswind speed predicts the displacement of a fan blade to characterize the fan forced response under crosswind. Computations will be made on a high-bypass turbofan engine where such phenomena can occur and which was tested. Thus computed results will be compared to test results.
|
|---|
