乙醇/柴油混合燃料的配制、物性测量和对柴油机性能影响的模拟研究

Research on the Concoctions, Material Parameters and diesel engine performance simulation for the Blend Fuels of Ethanol and Diesel

摘要:

乙醇/柴油混合燃料具有减少对石油资源需求和降低柴油机排放的优势，但乙醇和柴油的分子极性不同，导致无法直接形成稳定均匀的混合燃料。本文选择丁醇、庚醇、生物柴油和聚山梨糖醇单油酸酯作为助溶剂，对比研究其助溶效果。然后按照不同乙醇体积百分比（10%、20%和30%）和温度范围（从5℃～60℃），进行混合燃料的密度、表面张力和粘度等物性参数测量，研究出其随浓度和温度变化的规律。最后模拟研究混合燃料对柴油机性能的影响，发现随乙醇体积百分比的增加，燃油雾化效果得到改善，壁面油膜逐渐减少，氮氧化物（NOx）和碳烟（soot）排放逐渐减少；发动机动力性逐渐下降，但是当量比油耗和燃烧噪声逐渐下降。乙醇体积百分比为10%时柴油机的综合性能最佳。

Abstract:

Blend fuels of ethanol and diesel have an advantage of decreasing request of petroleum resource and diesel engine exhaust emissions. But the molecular polarity of ethanol and diesel are different, it’s hard to form uniform and stability blend fuels without solubilizer. First, butanol, heptanol, biodiesel and sorbitan monooleate were chosen as the solubilizers. The solubilization capacity of these solubilizers were researched. Then the experiments on the ethanol-diesel blend fuels in different ethanol volume percentages (10%, 20% and 30%) and temperatures (from 5℃ to 60℃) were conducted. The experiential formulas about density, surface tension and viscosity varied with ethanol volume percentage and temperature were generalized. Finally, the simulation research for the effect of ethanol volume percentages on the diesel engine performance was conducted. With the ethanol volume percentage increasing, the fuel atomizing process improved, wallfilm mass decreased, NOx and soot emissions decreased, engine power performance penalized, while equivalent indicated specific fuel consumption and combustion noise reduced. The comprehensive performance of the diesel engine is the best when ethanol volume percentage is 10%.