Investigation on the coupling characteristics of curved micro-tube bundles with different support configurations

Abstract

The structural integrity of curved micro-tube bundles in aero-engine precoolers is critical for hypersonic flight safety and efficient thermal management. However, these bundles frequently suffer from severe flow-induced deformation and localized stress concentration under extreme operating conditions. To address this problem, this study establishes a three-dimensional thermo-fluid-structural coupling numerical model—incorporating micro-mechanical size effects—to investigate the mechanical response under combined thermal, fluid, and mechanical loads. Moving beyond previous studies that were mostly confined to straight tubes or uniform constraints, the novelty of this work lies in revealing the spatial regulation mechanisms of non-uniform constraint stiffness on fluid-structure interactions within complex curved geometries. The influence mechanisms of three specific support strategies, namely uniform distribution, middle-densified, and ends-densified layouts, were systematically evaluated. Quantitative results indicate that: (1) under baseline conditions, maximum deformation occurs at the mid-span while stress concentrates at the end sidewalls; (2) the middle-densified configuration paradoxically restricts central displacement but amplifies the maximum deformation to 45.01 mm (1.57 times that of the uniform support), thereby exacerbating localized stress; (3) the ends-densified support emerges as the optimal strategy, effectively suppressing global bending modes and restricting the maximum deformation to 28.25 mm, while successfully maintaining the peak stress at 307.61 MPa (safely below the material yield strength). In conclusion, strategically concentrating support stiffness at the boundaries optimizes load transfer and enhances structural stability, providing a certain theoretical basis for the optimal design of next-generation high-performance micro-tube heat exchangers.