甲醇-柴油混合燃料发动机喷雾及燃烧过程的数值模拟

Numerical Simulation of Spray and Combustion of Methanol-Diesel Blends

分别建立了纯柴油发动机及甲醇-柴油混合燃料发动机喷雾燃烧过程的多维数值模型,并用试验结果对计算值进行了可行性验证。模拟计算结果表明,在不改动柴油机结构的情况下,掺烧15%的甲醇后,滞燃期变长;喷雾贯穿距离缩短,破碎能力增强,油滴索特平均直径也有所降低,这表明掺烧甲醇后具有较好的喷雾均匀性;燃油浓度场均匀性得到改善,与空气混合效果更好;Soot与NO排放均有明显降低。

The multi-simulation of spray and combustion process of diesel engine and methanol-diesel engine was carried out.Calculation data are validated by experimental results,which shows that the simulation is credible.The results show：if 15% methanol（M15） is used in diesel engine without any variation,the ignition delay period becomes longer;the penetration length is shorter,the break-up capability boosts up and the sauter diameter of droplet decreases,and all these suggest that the methanol-diesel blends engine has better spray characteristics;M15 has a better mixing with air,and concentration field is more uniform;the state of emission of NO and Soot has very great improvement.