燃料浓度对可燃气云燃烧流场的影响

Effect of fuel concentration on the flow field in flammablevaporcloud deflagration

气云燃烧爆炸过程中的流动对灾害具有重要影响。以不同浓度,半径为0.5m的无约束半球形乙炔气云为例,采用计算流体动力学方法,研究了燃料浓度对可燃气云初始气云区以外气流速度、乙炔体积分数和化学反应速率的影响规律。研究结果表明由于气云燃烧中流场相互作用,使得气云体积不断增大,同时将燃料推动到初始气云区外。随着气云中乙炔初始体积分数的增加,气云初始区外会获得更多燃料,使得反应区增大。乙炔初始体积分数为5%的可燃气云,化学反应区为初始体积的1.4倍;乙炔体积分数为13%和23%的可燃气云,化学反应区可达初始体积的2倍;乙炔体积分数为33%和43%的可燃气云,化学反应区能达初始体积的3倍。

The flow fields in flammable vapor cloud deflagration have significant effects on the deflagratioru We investigate the effects of fuel concentration on flow velocity, G2 H2concentration, and reaction rate with computational fluid dynamics code. The flammable acetylene vapor cloud with 0. 5 m radius is simulated. The results show that the fuel will be pushed out of the origin zone because of the interaction between flow fields. With the increase of the C2 H2 concentration, more fuel will be driven out of the origin zone and thus expands the reaction zone. The chemical reaction zone can expand to a volume 1.4 times of the original volume at an initial concentration of 5%. When the initial concentration is 13% or 23%, the chemical reaction zone can expand to twice of its original volume, and to three times when the initial concentration reaches 33% or 43%.