初始压力对甲烷-空气预混气体燃烧特性的影响研究

Effect of initial pressure on combustion characteristics of methane-air mixtures

试验采用高速纹影系统和压力传感器对甲烷-空气预混气体定容燃烧特性进行了研究,分析了不同初始压力对火焰传播特性的影响以及定容燃烧弹中压力的变化规律。试验结果表明:随着初始压力的增加,火焰的传播速度变化不大,并且有减小的趋势,当初始压力超过0.14 MPa后火焰的燃烧速度会发生突变而增大;初始压力的变化对定容燃烧弹中燃烧压力的影响十分显著,当初始压力为0.10 MPa时,最大燃烧压力Pmax=0.703MPa;而在初始压力为0.16 MPa时,最大燃烧压力Pmax=1.42 MPa;随着初始压力的增加,火焰变得愈发的不稳定。

The combustion characteristics of methane-air mixtures in the constant-volume bomb were studied in the case of different initial pressures by means of schlieren system, pressure sensor and high-speed camera. On the basis of the experiment, a profound analysis of the influences of initial pressures on combustion characteristics of methane-air mixtures was made. The results showed that the greater the initial pressure, the greater the flame propagation speed becomes, nevertheless, a turning shift occurs at in the initial pressure of 0.14 MPa, the flame propagation speed gets higher. The initial pressure has a strong effect on the combustion pressure, and so does the flame stability, the combustion pressure tends to increase with the increase of the initial pressure. According to the flame propagation pictures taken by high-speed camera, it is found that flame stability decreases with the increase of initial pressure.