Abstract:

The flammability limit of ethane in O₂/inert gases （N₂， Ar， CO₂） atmosphere was experimentally determined in a 5 L constant volume combustion bomb. Among the three inert gases， CO₂ is of the greatest influence on the flammability limit. For the lower flammability limit， Ar and N₂ decreased it slightly， while CO₂ increased it from 3.40% to 4.65%. The upper flammability limit changed more significantly； as the inert gas concentration increased from 10% to 80%， CO₂ reduced it from 51.5% to 8.0%， a reduction of 43.5%， while Ar and N₂ reduced it by 39.0% and 40.0%. The dilution， chemical， thermodynamic， and radiation effects of inert gases were separated with the limiting laminar burning velocity method. The results show that N₂ only produces the effects of dilution and radiation， while Ar and CO₂ produce four effects. At the lower flammability limit， the dilution effect of N₂ is the strongest， accounting for 99.2% of the total effect， and the thermodynamic effect of Ar and CO₂ is the largest， accounting for 64.4% and 51.4% of the total effect， respectively. For the upper flammability limit， the dilution effect is always of the greatest influence.

Key words: gaseous fuel, flammability limit, inert gas, limiting laminar burning velocity method, reaction kinetics analysis