Research on stiffness interaction between design regions of serpentine nozzle under fluid-solid-thermal coupling

As a typical large-scale high-temperature thin-walled structure, the structural design of the serpentine nozzle is critically important for both the operational performance and reliability of the component. The fluid-solid-thermal coupling numerical simulation was employed to investigate stiffness interaction between design regions of serpentine nozzle under different regional thicknesses. The results indicated that increasing the uniform wall thickness effectively suppressed localized large displacement and stress concentration caused by pressure loads. The stiffness of region 1 was significantly affected by the wall thickness variation of adjacent regions, an influence that could even surpass that of their own thickness. The impact of wall thickness variation on structural response differed significantly across nozzle regions, creating distinct advantage zones for uniform versus regional thickness models. Within the maximum displacement range of 0.55–1.00 mm, the regional thickness model reduced structural weight by up to 18.5% compared to the uniform thickness model under equivalent displacement levels, demonstrating superior structural utilization efficiency. The coupling effects between regions were asymmetric, regions 3–4 exhibited pronounced mutual influence, whereas the coupling with region 5 was relatively weak. Furthermore, stiffness coupling coefficients followed distinct trends with increasing wall thickness. The coefficients for regions 5–6 showed complex variation tendencies, while the coefficients of region 1 and region 6 exceeded the critical value of 1 as wall thickness increased. The results systematically clarify the specific patterns of stiffness coherence among multiple design regions, providing a crucial basis for structural design to optimize serpentine nozzle performance.