基于扩散点火理论的高压氢气泄漏自燃研究

运用扩散点火理论对高压氢气泄漏到下游管道内的自燃点火情况进行了分析。利用激波管流动理论讨论了氢气射流前端激波加热区域的参数变化情况，分析了前沿激波强度、均匀区压力和温度与初始压力的关系，给出了高压氢气泄漏到下游管道后，预测前沿激波强度、均匀区压力和温度的数学方程，建立了判断高压氢气泄漏到下游管道内是否发生自燃点火的函数表达式。提出了理论点火临界压力的概念，计算发现氢气的理论点火临界压力明显低于其他几种常见的气体燃料。讨论了影响泄漏自燃发生的可能因素，结果可为预防高压储氢泄漏自燃提供科学依据。

Study on self-ignition caused by high-pressure hydrogen heak based on a diffusion ignition theory

Releases of pressurized hydrogen can be spontaneously ignited without any clearly identifiable ignition sources. Theoretical analysis based on diffusion ignition theory is carried out on the self-ignition scenarios where high-pressure hydrogen gas is momentarily discharged via a downstream pipe into air. The changes of parameters in the region between the hydrogen jet front and the leading shock wave are analyzed using the theory of shock tube flow. The leading shock strength, shocked-air temperature and pressure depend on the initial pressure of the compressed hydrogen. The mathematical equations for calculating the strength of shock wave and the pressure and temperature of the shocked-air region are given. A mathematical expression is established to predict whether the spontaneous ignition can occur when high-pressure hydrogen emits from a tank into air through a downstream tube. Furthermore, the concept of theoretical critical pressure of ignition is proposed. The critical pressure is defined as the minimum initial pressure required for the temperature of shocked-air achieving to the self-ignition temperature in theory. And it is found that the theoretical critical pressure of ignition of hydrogen is significantly lower than other common gaseous fuels. The influencing factors of auto-ignition were also discussed. The present work can provide a scientific basis for preventing and mitigating the spontaneous ignition occurring in high-pressure hydrogen storage and transportation.