低温脂肪酸甲酯乳化油掺水量对雾化特性的影响

Effect of Lower Fatty Acid Methyl Ester Emulsified Oil Temperature with Water Content on Spray Characteristics

冷启动一直是柴油发动机的一个问题,为改善冷启动阻碍燃油着火及不完全燃烧的问题,以FAME-水乳化油为研究对象,研究了乳化油在低温(263 K、268 K、273 K)下不同混合比例(含水量5%、10%、15%)的喷雾特性,低温和含水量对雾化特性的影响,并与较高温度(283~323 K)作比较,以提供解决冷启动有价值的见解。结果表明:乳化油在较低温条件下,由于表面张力较大使得液滴不易发生破碎,燃油雾化效果差。同时随着乳化油含水量的增加,索特平均直径SMD明显减小,但喷雾液相贯穿距、锥角变化不大。随着燃油温度的升高,液相贯穿距减小,而喷雾锥角在增大,油温313K之后雾化效果较好,同时SMD减小也较为明显。

The cold start issue has been a problem in diesel engines.To improve the problems of the cold start pre-venting ignition and incomplete combustion,the spray characteristics is tested by utilizing FAME-water emulsified fuel with lower fuel temperature（263 K,268 K,273 K） at mixing ratio（water content 5%,10%,15%）.And the effect of lower fuel temperature and water content on liquid penetrate length,Sauter Mean Diameter and spray cone and making comparison with spray characteristics at higher temperature（283 - 323 K） to provide valuable insights for solving the cold start problem.The results indicate that,emulsified oil at lower temperature conditions have poor atomization due to the larger surface tension making the droplets break not easily.With the increase of water content in emulsified fuel,sauter mean diameter SMD decreases obviously,but the liquid penetration and cone angle have no big change.As rising the fuel temperature,the liquid penetration diminishes,the corresponding cone angle increases,the atomization after 313 K is better,and SMD decreases.