为研究隧道内氢能源列车高压储氢泄漏和扩散的演变规律, 该文采用数值模拟方法, 建立了隧道和列车物理模型, 结合湍流模型与Molkov虚喷嘴模型, 系统分析了氢气泄漏速度场、动量变化和三维空间内氢气体积分数分布特征。结果表明: 氢气泄漏后速度方向受隧道壁面影响快速变化, 沿隧道壁面呈梯度分布; 在靠近隧道出口处, 速度呈衰减趋势; 各区域密度变化平缓, 横向动量变化逐渐趋于均匀。在氢气扩散方面, 纵向扩散中, 氢云沿隧道顶棚纵轴线呈放射状对称分布, 泄漏口下游0~60.0 m氢云表层内形成高体积分数积聚区; 横向扩散中, 氢云受湍流混合作用呈对称扩展趋势, 并在泄漏后期覆盖整个隧道宽度; 竖向扩散中, 氢云因浮力主导主要聚集于3.0~5.0 m高度的顶层空间, 底层氢云体积分数始终低于安全阈值。该文研究结果可为氢能源列车在隧道场景的安全应用提供参考。

Objective: As a novel, clean, and efficient energy source, hydrogen has emerged as a cornerstone of sustainable transportation, facilitating the rapid development and deployment of hydrogen-powered trains. While current research mainly explores relatively idealized open environments or simple confined volumes, the unique challenges posed by semi-enclosed, longitudinal tunnel geometries remain insufficiently investigated. Specifically, the dispersion and transport mechanisms of hydrogen following high-pressure leakage in the tunnel scenario, along with the resulting hydrogen concentration distribution, remain to be investigated. Furthermore, there is a lack of connection and analysis between the evolution of the velocity field and the variations in momentum flux following high-pressure hydrogen leakage. Methods: To investigate the evolution law of high-pressure hydrogen leakage and dispersion within tunnels, a numerical modeling approach was employed to establish physical geometry models of the tunnel and train. By integrating the turbulence model with the Molkov virtual nozzle model, the evolution of the velocity field, the variations in the hydrogen-leakage momentum flux, and the three-dimensional concentration distribution profiles were systematically analyzed. Results: After hydrogen leaked, its jet impinged on the tunnel ceiling, followed by rapid lateral dispersion and downward flow along the tunnel ceiling. During this process, the hydrogen momentum vector underwent multiple reorientations at the wall, which led to a rapid decrease in its momentum. Consequently, the momentum flux distribution exhibited a distinct gradient distribution along the tunnel ceiling. The velocity decayed significantly toward the tunnel exits, where density variations across the different zones remained negligible; the lateral momentum gradually homogenized. Hydrogen dispersion exhibited radial symmetry along the longitudinal axis of the tunnel ceiling. Furthermore, a high-concentration accumulation zone was identified within the flammable-hydrogen cloud surface layer, extending 0-60.0 m downstream from the leakage source. Laterally, the cloud expanded symmetrically under the influence of turbulent mixing, eventually spanning the entire width of the tunnel. Vertically, buoyancy-driven effects confined the hydrogen cloud accumulation to the upper 3.0-5.0 m of the tunnel, while concentrations in the lower strata remained consistently below the safety threshold. The initial momentum of the hydrogen jet significantly influenced its spatial distribution and dispersion. In the near-field region proximal to the leakage source, the high-velocity hydrogen jet impinged on the tunnel ceiling and was forced downward along the tunnel walls, thereby preventing hydrogen accumulation near the ceiling close to the wall. However, when the distance from the leakage source was relatively large, the velocity vector of hydrogen was lost, as hydrogen dispersion and transport at that time were mainly affected by buoyancy. Consequently, hydrogen rose from its previously downward-spread position and accumulated gradually on the tunnel ceiling. Therefore, a hydrogen-concentration peak appeared at a relatively distant position. Conclusions: The findings of this study provide basic data support for hydrogen-related parameters for analyzing hydrogen leakage in hydrogen-powered trains in tunnel scenarios, which is conducive to the application and promotion of hydrogen energy in non-traditional enclosed scenarios, such as tunnels.