煤气火焰传播规律及其加速机理研究

Study on flame propagation and accelerationmechanism of city coal gas

研究了煤气/空气预混气在两端封闭管道中的火焰传播加速现象和管道中有无障碍物时火焰的加速机理,认为火焰加速是由于火焰前未燃气体被前驱压缩波加热和障碍物诱导的湍流区对燃烧过程的正反馈造成的。实验结果表明,障碍物存在时,最大爆炸压力可提高20%,与理论计算一致;火焰传播特性随煤气浓度的变化而改变;障碍物阻塞比对火焰的速度和压力都有一定影响。

An experimental study on acceleration mechanism of flame propagation of city coal gas-air mixture was conducted in a closed obstructed duct with 80 mm diameter and 21 mm length, and acceleration mechanism of flame with or without obstructions is researched. Acceleration mechanism of flame propagation owes mainly to the positive feedback of unburned gas heated and compressed by the leading compression wave and the turbulence region induced by obstacles for combustion process. The experimental results indicate that the maximum explosion pressure can increase by 20% when the obstacles are present, and the maximum explosion pressure of theoretical computation results agree with the experimental data. The flame propagation characteristics with the variation of equivalence ration of city coal gas-air mixtures are described. The circular plates number and blockage ratio have some effects on the flame velocity and overpressure.