Fuel cell vehicles (FCV) and other hydrogen systems with pressurized hydrogen has a safety hazard of spontaneous ignition during its sudden release into the tube. Tube parameter is a key factor affecting the spontaneous ignition of pressurized hydrogen. In this paper, a numerical study on the spontaneous ignition of pressurized hydrogen during its sudden release into the tube with varying lengths and diameters is conducted. The models of Large Eddy Simulation (LES), Eddy Dissipation Concept (EDC), Renormalization Group (RNG), 10-step like opening process of burst disk and 18-step detailed hydrogen combustion mechanism are employed. 6 cases are simulated based on the previous experiments. Numerical results show that the possibility of spontaneous ignition of pressurized hydrogen increases inside the longer and thinner tubes, which agrees with the experimental results. The increasing of tube length has little influence on the shock wave formation and propagation inside the tube. However, there exists critical tube lengths for the generation of Mach disk and the normal shock wave: the maximum and minimum distances for the generation of the Mach disk in 10 mm diameter tube are 7.8 and 6.7 mm, respectively. As for the normal shock wave, these critical values are 22.1 and 19.4 mm, respectively. In addition, the formation times and initial positions of Mach disk and normal shock wave are delayed inside the thicker tube. Due to the shock-affected time increases with the increasing of tube length, the temperature could rise to the critical ignition temperature and triggers the spontaneous ignition due to the sufficient tube length even though the less hydrogen/air mixture and the contact surface with lower temperature is produced inside the thicker tube. Finally, a simple time scale analysis is conducted.

燃料电池汽车 (FCV) 和其他带有加压氢气的氢气系统在突然释放到管道中时存在自燃的安全隐患。管参数是影响加压氢气自燃的关键因素。在本文中，对加压氢气突然释放到不同长度和直径的管中时自燃的数值研究进行了。采用大涡模拟(LES)、涡耗散概念(EDC)、重整化群(RNG)、爆破片10步式打开过程和18步详细氢燃烧机理模型。在前面的实验的基础上模拟了6个案例。数值结果表明，在较长和较细的管内，加压氢气自燃的可能性增加，与实验结果一致。管长的增加对管内激波的形成和传播影响不大。然而，对于马赫盘和法向激波的产生存在临界管长：在直径为 10 mm 的管中产生马赫盘的最大和最小距离分别为 7.8 和 6.7 mm。对于法向冲击波，这些临界值分别为 22.1 和 19.4 毫米。此外，马赫盘和法向激波的形成时间和初始位置在较粗的管内被延迟。由于冲击影响时间随着管长的增加而增加，即使在较粗的管内产生较少的氢气/空气混合物和较低温度的接触表面，温度也可能升高到临界点火温度并由于足够的管长度而触发自燃。最后，进行简单的时间尺度分析。