气动热力耦合作用下结构累积热变形的演化特性及影响

Evolution characteristics and effects of structural cumulative thermal deformation under aerodynamic-thermal coupling

  • 摘要: 新一代大尺度轻质飞行器长航时高速飞行时,累积热变形问题比传统飞行器更显著,对飞行不利。针对典型大长细比空腔平板结构,采用高保真全数值的气动力/热/结构多物理场耦合分析方法,开展了气动热和气动力耦合作用下结构变形演化特性、热/力因素作用机理及变形对飞行性能的影响研究。研究结果表明,在长时间严酷加热条件下,空腔结构的热变形特征主要由热因素的时间累积效应和力因素的瞬时作用共同决定,其演化过程呈现3个演化阶段:第一阶段以冷壁面结构快速升温作用为主导,变形急剧增加;第二阶段以结构升温后持续气动加热作用为主导,变形缓慢增加并回落;第三阶段达到热/力作用趋于平衡的充分发展状态,变形稳定。与实芯结构规律不同,空腔结构的变形规律存在较为特殊的回落过程,该特性在不同马赫数和攻角下均比较一致。累积热变形演化行为引发了气动特性的非线性变化,伴随整个飞行历程,进一步带来升阻力和俯仰力矩偏差等不利影响,这一新的影响和挑战亟需在未来新一代高速飞行器设计中加以考虑和应对。

     

    Abstract: Next-generation large-scale lightweight aircraft experience more significant cumulative thermal deformation during prolonged high-speed flight than conventional aircraft, adversely affecting flight performance. Focusing on typical high-aspect-ratio cavity plate structures, this study adopted a high-fidelity fully numerical aero-thermal-structural coupled analysis method to investigate: (1) structural deformation evolution under coupled aerodynamic heating and loading, (2) thermal-mechanical interaction mechanisms, and (3) deformation effects on flight performance. The results showed that under prolonged severe heating conditions, the thermal deformation of cavity structures was determined by the combined effects of time-accumulated thermal factors and instantaneous mechanical loads, exhibiting three distinct evolutionary stages: Stage I (rapid deformation dominated by cold-wall heating), Stage II (gradual deformation increase followed by recession under continued aerodynamic heating), and Stage III (stabilized deformation through thermal-mechanical equilibrium). Unlike solid structures, cavity structures demonstrated this unique recession behavior consistently across different Mach numbers and angles of attack. The cumulative thermal deformation caused nonlinear variations in aerodynamic characteristics throughout the flight, leading to adverse effects such as deviations in lift-to-drag ratios and pitching moments. These findings highlight the need to address such thermal deformation effects in the design of future high-speed aircraft.

     

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