AERODYNAMIC DEFORMATION EXPERIMENT OF SERPENTINE NOZZLE FOR TURBOFAN AND ANALYSIS OF FLUID-STRUCTURE INTERACTION METHOD

The serpentine nozzle is a crucial component in stealth aircraft for reducing detectable signals. This paper compares the aerodynamic-deformation coupling characteristics of the serpentine nozzle under unidirectional and bidirectional fluid-structure interaction (FSI) methods and verifies the accuracy of different coupling methods through experimental research. The results indicate that the deformation distribution trends of the serpentine nozzle are consistent under both unidirectional and bidirectional FSI methods. However, the overall deformation is greater with the unidirectional coupling method, with a maximum deformation of 32.2 mm compared to 27.6 mm for the bidirectional coupling method. The aerodynamic performance of the serpentine nozzle decreases after undergoing FSI, with the total pressure recovery coefficient reduced by 1.2% and the thrust coefficient reduced by 0.5% under unidirectional coupling. Under bidirectional coupling, the total pressure recovery coefficient is reduced by 1.1% and the thrust coefficient by 1.75%. Based on experimental and numerical studies, the maximum error for the unidirectional FSI method is 23.4%, while for the bidirectional FSI method, it is 9.1%. The bidirectional coupling method can accurately simulate the aerodynamic deformation characteristics of the serpentine nozzle in turbofan engines, aligning more closely with physical laws under real-world conditions.