管道内甲烷-空气预混火焰传播特性的实验与数值模拟研究

Experimental and numerical study on flame propagation and structure behaviors of methane-air premixed combustion in tube

采用高速纹影摄像系统、压力传感器等对小型水平封闭管道内甲烷-空气预混燃烧火焰的传播过程进行了实验研究,得到了火焰锋面结构、传播速度和压力随时间的变化关系.研究结果表明,管道内预混火焰传播过程中,火焰结构会发生明显变化,即从向未燃气体凸出的球形层流火焰转变成向已燃气体凹陷的V形湍流火焰,同时伴有火焰传播速度的减小、压力的不断增大.另外运用标准k-ε模型,对非定常时的甲烷预混燃烧火焰进行数值模拟,得到了与实验结果类似的火焰传播特性和火焰结构的变化规律.

The high speed Schlieren photography system and pressure sensors were used to investigate the flame propagation process of methane-air mixture in a small horizontal tube. The flame structure, propagation velocity and mixture pressure were obtained from the experiment. The results show that flame structure changes greatly in the flame propagation process, suddenly changing from a spherical laminar flame pointing forward to a V shape turbulent flame forming a cusp toward the burned gas. In this process, the velocity decreases but the pressure increases continuously. With the k-ε turbulent combustion model, unsteady premixed methane flame in a 2D matrix burner was numerically simulated. The characteristics of flame propagation and flame structure variation qualitatively agree with the experimental data very well.