掺氢对汽油预混燃烧特性的影响

Effects of Hydrogen Addition on Premixed Combustion Characteristics of Gasoline

为研究掺氢比和初始压力对汽油层流燃烧特性的影响,在定容燃烧试验系统内对初始温度为400 K,初始压力为0.10 MPa、0.15 MPa和0.20 MPa,掺氢比为0%、5%、25%、50%、75%、100%,当量比在0.7~1.6范围的汽油/H2混合气进行预混层流燃烧特性的试验研究,通过高速纹影图像采集系统记录了混合气火焰发展过程并对试验数据进行了分析计算。研究结果表明:相同当量比情况下,随着氢气的加入层流燃烧速度提高;纯汽油的层流燃烧速度峰值出现在当量比1.2处,随着掺氢比的提高层流燃烧速度峰值逐渐向浓混合气区移动;在低当量比时氢气的加入使火焰不稳定性增强,高当量比下则相反,氢气的加入改变了混合燃料的火焰不稳定性变化趋势;压力升高伴随着层流燃烧速度降低,且火焰不稳定性加剧。

In order to study the influence of hydrogen mixing ratio and initial pressure on laminar combustion characteristics of gasoline,the premixed laminar combustion characteristics of gasoline/hydrogen mixture with an equivalent ratio of 0. 7~1. 6 were studied experimentally. The initial temperature was 400 K,and the initial pressure was 0. 10 MPa,0. 15 MPa and 0. 20 MPa,and the hydrogen mixing ratio was 0%,5%,25%,50%,75%,100% in the constant volume combustion test system. The development process of the mixture flame was recorded by the high-speed schlieren image acquisition system,and the experimental data was analyzed and calculated. Results show that the laminar burning velocity increases with the addition of hydrogen at the same equivalence ratio. The peak value of laminar burning velocity of pure gasoline appears at the equivalence ratio of1. 2,and gradually moves to the dense mixed gas zone with the increase of hydrogen mixing ratio. At low equivalence ratio,the addition of hydrogen increases the flame instability. But it is opposite at the condition of high equivalence ratio where the addition of hydrogen changes the trend of flame instability of the mixed fuel. With the increase of the pressure,the laminar burning velocity decreases,and the flame instability increases.