Thermal–Solid Interaction Study of Serpentine Nozzle and Analysis on Structural Response Law

The serpentine nozzle effectively suppresses infrared radiation and radar signals from advanced aero-engine exhaust system. However, the extreme operating environment of thermal–solid interaction complicates the heat transfer of the flow inside the serpentine nozzle and the structural response of the nozzle itself. In this study, the internal flow heat transfer and the structural response of the serpentine nozzle were investigated numerically. Further, the parameter influence law of wall thickness was explored. The results show that the mechanism of the thermal-solid interaction is formed through the data transfer of the heat flux and the temperature at the interface between the flow field and structure field. The heat flux distribution of the nozzle under the bending configuration is non-uniform. The upper wall surface at the first bend and the lower wall surface at the second bend exhibit the highest heat flux. In the structural response, the temperature extremes appear on the upper wall at the first bend and the lower wall at the second bend. Subsequently, they shift to the inlet. The stress in the nozzle with a thickness of 3 mm first increases and then decreases, with a maximum stress of 139.43 MPa at t = 51.20 s. For nozzles of different thicknesses, the positions of the maximum stresses all appear at the outlet and the moments concentrate in approximately 50 s. However, with the increase in thickness, the maximum stress of nozzle increases continuously, and the maximum increases by 93% compared with the minimum.