掺氢比对甲烷-氧气爆轰特性的影响

Effects of hydrogen-blending ratio on detonation characteristics of premixed methane-oxygen gas

含氢多组分燃料由于其优良的燃烧特性逐渐成为研究关注的重点。为了对掺氢燃料的爆轰特性作进一步的研究,设计了长3 000 mm、管径30 mm的圆柱形半封闭燃烧室,对不同初压下的CH4-2O2、6CH4-H2-12.5O2、3CH4-H2-6.5O2(掺氢比分别为0%、5.1%、9.5%)3种预混合气的爆轰特性进行了实验研究,并采用烟熏膜、离子探针和压力传感器分别探测胞格结构、火焰位置和内部压力。结果表明,甲烷/氧气掺氢后可以有效提高爆轰波的传播速度,且掺氢浓度越高,传播速度越快;同时,氢气的掺入可减少管道出口处的速度亏损并在初始压力较低时加速火焰和激波的耦合,降低胞格尺寸,提高爆轰敏感性。

Hydrogen-doped fuel has gradually become the focus of research due to its excellent combustion characteristics. In order to further study the detonation characteristics of hydrogen-doped fuel, a cylindrical semi-enclosed tube with the length of 3 000 mm and the diameter of 30 mm was designed. The detonation characteristics of three premixed gases, CH4-2O2, 6CH4-H2-12.5 O2 and 3CH4-H2-6.5 O2(hydrogen ratio is 0%, 5.1% and 9.5%, respectively), were studied experimentally under different initial pressures. Smoked foils, ion probes and pressure sensors were used to measure the cell structures, the flame positions and the internal pressures, respectively. The results show that hydrogen-doped methane/oxygen can effectively increase the propagation velocity of detonation waves, and the higher the concentration of hydrogen, the faster the propagation velocity. In addition, hydrogen can reduce the velocity loss at the outlet of the tube and accelerate the coupling of flame and shock wave at lower initial pressures, reduce the cell size and improve detonation sensitivity.