جستجوی مقالات مرتبط با کلیدواژه « serpentine nozzle » در نشریات گروه « مکانیک »

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.

Serpentine nozzle can effectively suppress the infrared radiation signatures of the aero-engine exhaust system. However, it experiences the remarkable fluid-structure interaction (FSI) process at the work condition. In this paper, the deformation behavior of the serpentine nozzle and its flow characteristic were investigated numerically. Then, the influences of the wall thickness and the geometric configuration on the FSI effect were also explored. The results show that, the mechanism of the fluid-structure interaction is formed through the data transfer of the force and the displacement at the FSI interface. Under the FSI effect, there occur the ballon-like swellings at the second S passage, and the linear section bends upward along the Y direction. They induce the special flow features including the flow separation, the shock wave and the plume vector angle. As the value of the wall thickness increases from 3mm to 6mm, the maximum of the deformation displacement of the serpentine nozzle decreases 68.5mm. As compared to the uncoupled state, the variation of the axial thrust decreases from 2.70% to 0.70% at the coupled state. The circular-to-rectangular profile and the S-shaped passage enlarge the deformation behavior of the nozzle structure. The value of the axial thrust of the serpentine nozzle with 5mm wall thickness for the coupled state is lower 1.92% than these for the uncoupled state.