六组分替代柴油的单液滴蒸发特性模拟

Simulation of Single Droplet Evaporation Characteristics for Diesel Fuel Represented by Six-Component Mixture

为有效模拟实际柴油液滴的蒸发过程,以六种组分(甲苯、正癸烷、正十二烷、正十四烷、正十六烷和正十八烷)作为柴油的替代,构建了考虑辐射效应的多组分液滴蒸发的有效扩散模型,并与柴油液滴蒸发试验进行对比.结果表明:与单组分替代物相比,该六组分替代柴油的单液滴蒸发模型更能表征柴油在高温下的蒸发状态,且该六组分液滴初期蒸发较快、升温较慢,但总体生存时间增长,蒸发终了温度升高.液滴各组分表面质量分数快速减小(或增加),但中心质量分数只在蒸发后期稍有变化.

To make an accurate simulation of the complex components, a blend of six components（toluene, n- decane, n-dodecane, n-tetradecane, n-hexadecane and n-octodecane） was used as a representative for diesel. A multicomponent droplet vaporization model with thermal radiation absorption was built and validated to the experimental data. Calculations agree well with the experiments. Vaporization characteristics of diesel droplet evaporation are satis- factorily predicted by the six component blend. Compared with mono-component droplet（n-dodecane, n- hexadecane）, the evaporation rate of the six-component surrogate fuel becomes faster while the heating rate is slower in the initial evaporating period, but the droplet lifetime is longer and the droplet temperature is higher at the end. The surface mass fraction of each component changes quickly while that of the central one only changes a little in the later evaporation period.