An experimental investigation on the effects of continuous semicircular curved structure on spontaneous ignition during pressurized hydrogen suddenly release was conducted. An S-shaped tube with 700 mm in length and 10 mm in diameter was used in our experiments, and a straight tube with the same configuration was adopted for comparison. The results show that the continuously generated rarefaction waves and reflected shock waves make the pressure curves in the S-shaped tube more complicated. Meanwhile, the mean velocity and intensity of the leading shock wave undergo considerable attenuation when it propagates in the S-shaped structure. By comparing with the straight tube, the minimum critical pressure condition for spontaneous ignition in the S-shaped tube is slightly difficult to reach, but the difference is not huge. Nevertheless, the S-shaped structure can effectively promote hydrogen-air mixing and make combustion more intense. A secondary overpressure peak detected by the pressure transducer near the nozzle occurs in the spontaneous ignition cases and no such pressure increase is caught in the non-ignition cases. The transition from spontaneous combustion flame to a jet flame at the nozzle and the complete out-tube jet flame development process are captured and discussed.

进行了连续半圆形弯曲结构对加压氢气突然释放过程中自燃的影响的实验研究。在我们的实验中，使用了长度为700 mm，直径为10 mm的S形管，并采用具有相同构造的直管进行比较。结果表明，连续产生的稀疏波和反射冲击波使S形管的压力曲线更加复杂。同时，超前冲击波在S形结构中传播时，其平均速度和强度会发生相当大的衰减。与直管相比，S形管中自燃的最小临界压力条件很难达到，但相差不大。不过，S形结构可有效促进氢气与空气的混合，使燃烧更加激烈。由压力传感器在喷嘴附近检测到的二次过压峰值出现在自燃情况下，而在非点燃情况下则没有发现这种压力升高。捕获并讨论了从喷嘴处的自燃火焰到射流火焰的过渡以及整个管外射流火焰的形成过程。