中文摘要：

运用三维CFD软件，建立柴油机分别燃用纯柴油和小桐子油的计算模型．分析了柴油机燃用2种燃油的燃烧过程，模拟了喷雾的发展历程，通过在一台单缸直喷式柴油机上燃用柴油、小桐子油的试验来验证模型，模拟所得结果与试验结果较为吻合．通过对2种燃料的油滴颗粒发展和缸内燃油质量分数分布进行比较，对喷雾特性差异的成因进行了探讨．结果表明：不同燃油的质量分数分布变化的趋势大体相同，与柴油相比，小桐子油在喷射的初始阶段的喷射速度较柴油的略大，但主喷射期的喷射速度较低，油束的贯穿距离较小，小桐子油的喷射时间较早，在开始喷射后，小桐子油的质量分数分布变化速度明显小于柴油，到了燃烧后期，其燃油质量分数较高的区域较大．

英文摘要：

Based on three dimension CFD software, a simulation model was established for the work processes of diesel engine fueled with diesel or Jatropha curcas oil. The combustion process and spray de- velopment process of different fuels were simulated. The verifying of proposed model on single-cylinder direct injection diesel engine illuminates that simulation results are well consistent with test results. The spray development process and the fuel mass fraction distribution of 2 fuels were compared to discuss the spray difference. The results show that the distribution variation tendency of fuel mass fraction for diffe- rent fuels is similar. The spray speed of Jatropha curcas oil is slightly larger at early injection stage and slower at main injection stage than those of diesel with low spray penetration. The injection timing of Jatro- pha curcas oil is early with smaller fuel mass fraction variation velocity than that of diesel. The zone of high fuel mass fraction of Jatropha curcas oil at later combustion stage is larger than that of diesel.