【摘要】 在定容燃烧弹内研究了初始条件为常温常压的天然气—氢气—空气混合气火焰传播规律,得到了不同掺氢比例和燃空当量比下混合气的层流燃烧速率、质量燃烧流量和马克斯坦长度,结合火焰传播照片,分析了火焰的稳定性并预测了大尺寸火焰稳定性的演变趋势。研究结果表明,随着天然气中掺氢比例的增加,混合气的燃烧速率增加,且增长速率逐渐加快,马克斯坦长度值减小,火焰的稳定性下降。各种掺氢比例下,随当量比的增加,马克斯坦长度值增加,火焰的稳定性增加。掺氢比例高于800/0时,随着火焰的传播,其不稳定性将明显增加。更多还原

【Abstract】 Flame propagation characteristics of natural gas-hydrogen-air mixtures were studied in a constant volume combustion bomb by analyzing the flame images.Initial temperature and pressure of the mixtures were set at 300 K and 0.1 MPa respectively.Laminar burning velocities,mass burning fluxes and Markstein lengths were obtained at various ratios of hydrogen to natural gas and equivalence ratios,and flame stability was analyzed and the stability tendency was estimated when flames grow to larger sizes.The results show that laminar burning velocity increases with the increase of hydrogen fractions in the fuel blends,while the increasing rate becomes largely at high hydrogen fraction.Markstein length decreases and flame instability increases with the increase of hydrogen fraction.For a fixed hydrogen fraction,Markstein length shows an increase and flame stability increases with the increase of equivalence ratios.When hydrogen fraction in the fuel blends is over 80⁰/₀,the flame instability will be remarkably increased.更多还原