Analysis of near stall condition of high bypass fan rotor based on airworthiness certification

Abstract

In order to ensure flight safety, the near stall condition test is one of the most important steps in the airworthiness certification phase of civil aircraft. The twisted and swept fan is one of the most important components of the high bypass ratio engine. The unsteady flow field of the fan rotor was calculated by CFD simulation. The unsteady flow at the tip of blades is an important cause of the development of the fan rotor from near stall condition to stall condition. Dynamic mode decomposition method (DMD) was applied to analysis unsteady flow field of the blade tip area. And compressed sensing dynamic mode decomposition (CPDMD) method was tried to deal with massive grid based on dynamic mode decomposition method. The dynamic mode decomposition method successfully separates the flow structure of the unsteady flow field. The compressed sensing dynamic mode decomposition method compresses the initial flow field snapshot to obtain low-dimensional flow field data. Then the DMD modality is got by analyzing the low-dimensional flow field. Finally, the DMD mode with the initial flow field snapshot dimension is obtained. So the CPDMD method effectively reduces algorithm runtime and reduces the computational resource requirements. This provides the possibility to process a large amount of flow field data that would otherwise be impossible to process.