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中文核心期刊

稀薄气体流动中的气固界面适应系数研究进展

RESEARCH PROGRESS ON GAS-SURFACE INTERACTION ACCOMMODATION COEFFICIENTS IN RAREFIED GAS FLOWS

  • 摘要: 气固界面适应系数是量化气体分子与固体壁面碰撞过程中动量和能量交换的核心参数, 对临近空间飞行器和超低轨航天器气动设计具有关键影响. 本文系统梳理了切向动量适应系数和能量适应系数的研究进展, 围绕适应系数在不同稀薄流动流域的作用机制, 阐明微观散射行为向宏观输运量的映射关系. 通过整合热丝法、分子束实验、微通道流量法、在轨测量等实验手段, 并结合分子动力学模拟对晶格振动、表面形貌与吸附状态的原子尺度描述, 归纳了气体参数(种类、入射速度、角度、温度)、固体参数(表面粗糙度、温度、吸附特性)以及气固相互作用势能参数对适应系数的影响规律. 结果表明, 适应系数具有明显的多因素耦合特性: 表面粗糙度、相互作用强度以及气体吸附程度的增强通常有助于提高适应程度; 入射速度与体系温度的升高会改变分子散射机制, 引发适应系数的非单调变化. 当前, 实验方法可提供直观的物理测量, 分子动力学模拟则有助于揭示微观机制, 但仍面临以单因素分析为主、多参数耦合机制不清、实验与模拟数据一致性不足等问题. 未来需聚焦固体表面粗糙度量化、气体吸附行为表征、多因素耦合模型构建及真实飞行环境验证, 以期为新一代稀薄流域飞行器气动设计提供更精确的理论支撑.

     

    Abstract: Gas-surface interaction accommodation coefficients quantify the exchange of momentum and energy during molecule-wall collisions. These coefficients are pivotal to modeling boundary effects in rarefied flows, with direct implications for the aerodynamic design and thermal management of near-space vehicles and ultra-low orbit spacecraft. This review synthesizes recent progress on tangential momentum and energy accommodation coefficients across rarefied flow regimes, with emphasis on underlying mechanisms that link microscopic scattering to macroscopic transport and on how these mechanisms are represented in engineering models. By integrating experimental approaches (including the hot-wires method, molecular beam scattering experiments, microchannel flow experiments, and on-orbit measurements) with molecular dynamics simulations that resolve lattice vibration, surface morphology, and molecule adsorption states at the atomic scale, the study identifies the governing laws of accommodation coefficients as influenced by gas properties, surface characteristics and gas-surface interaction potentials. The discussion covers the roles of gas species, mass, incident velocity and angle, and temperature, together with surface roughness, wall temperature, adsorption coverage, and potential well depth. Results indicate that accommodation coefficients are shaped by strong multi-factor coupling: Enhanced surface roughness, stronger interaction potentials, and increased gas adsorption generally raise accommodation coefficients, while higher incident energy and system temperature can induce non-monotonic variations by modifying molecular scattering mechanisms. At present, experimental methods provide direct macroscopic measurements with traceability, while molecular dynamics simulations reveal atomistic processes with precise control of surface state and interaction parameters. Nonetheless, challenges remain, including the predominance of single-factor analyses, limited understanding of multi-parameter coupling mechanisms, and inconsistencies between experimental and simulation data. Future efforts should emphasize quantifying surface roughness, characterizing gas adsorption behavior, developing multi-factor coupling models, and validating results under realistic flight conditions, thereby providing more accurate theoretical support for the aerodynamic optimization of next-generation vehicles in rarefied flow environments.

     

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