Abstract:

The effects of component concentration and equivalence ratio on the explosion characteristics of hydrogen/dimethyl ether/methane ternary mixed gas fuel were systematically studied by using the constant volume combustion bomb explosion experimental platform and high-speed schlieren camera technology. The results show that the average flame propagation speed S_a increases monotonically with the increase of hydrogen concentration X_{{\mathrm{H}}_{\mathrm{2}}} and decreases monotonically with the increase of dimethyl ether concentration X_DME. Also S_a decreases monotonically with X_{\mathrm{C}{\mathrm{H}}_{\mathrm{4}}}. The variation of explosion pressure peak p_max with X_{{\mathrm{H}}_{\mathrm{2}}} is strongly affected by equivalence ratio φ. When φ= 0.8, 1.0 and 1.2, p_max increases slowly and linearly with X_{{\mathrm{H}}_{\mathrm{2}}}, and then increases rapidly with X_{{\mathrm{H}}_{\mathrm{2}}}; While when φ=0.6, 1.4 and 1.6, p_max continuously increases linearly with X_{{\mathrm{H}}_{\mathrm{2}}}. Meanwhile, p_max decreases linearly with the increase of X_{\mathrm{C}{\mathrm{H}}_{\mathrm{4}}}, but p_max can be divided into two periods with the change of X_DME. In addition, X_{{\mathrm{H}}_{\mathrm{2}}} is positively correlated with the maximum pressure rise rate (dp/dt)_max, and X_{\mathrm{C}{\mathrm{H}}_{\mathrm{4}}} is negatively correlated with (dp/dt)_max. However, X_DME has little effect on (dp/dt)_max. The combustion time t_c has a linear relationship with X_{{\mathrm{H}}_{\mathrm{2}}} and X_{\mathrm{C}{\mathrm{H}}_{\mathrm{4}}}. Conversely, the influence of X_DME on t_c is more complicated, which is related to φ.

Key words: hydrogen, dimethyl ether, methane, explosion, pressure

摘要：

利用定容燃烧弹爆炸实验平台结合高速纹影摄像技术，系统研究了组分浓度和当量比对氢气/二甲醚/甲烷三元混合气体燃料爆炸特性的影响。结果表明：平均火焰传播速度S_a随氢气浓度X_{{\mathrm{H}}_{\mathrm{2}}}的增加单调递增，随二甲醚浓度X_DME和甲烷浓度X_{\mathrm{C}{\mathrm{H}}_{\mathrm{4}}}的增加单调递减。压力峰值p_max与X_{{\mathrm{H}}_{\mathrm{2}}}的关系受到当量比φ的强烈影响，当φ=0.8、1.0和1.2时，p_max随X_{{\mathrm{H}}_{\mathrm{2}}}先缓慢线性增加然后快速增加；而当φ=0.6、1.4和1.6时，p_max始终线性增加；同时，p_max随X_{\mathrm{C}{\mathrm{H}}_{\mathrm{4}}}线性递减，而随X_DME的变化可分为两个时期。X_{{\mathrm{H}}_{\mathrm{2}}}与最大压力上升速率(dp/dt)_max呈正相关关系，X_{\mathrm{C}{\mathrm{H}}_{\mathrm{4}}}与之呈负相关关系，而X_DME对(dp/dt)_max的影响不大。燃烧时间t_c与X_{{\mathrm{H}}_{\mathrm{2}}}和X_{\mathrm{C}{\mathrm{H}}_{\mathrm{4}}}存在线性关系；而X_DME对t_c的影响较为复杂，与φ有关。

关键词: 氢气, 二甲醚, 甲烷, 爆炸, 压力