Modeling study of soot formation and oxidation in di diesel engine using an improved soot model
Modeling study of soot formation and oxidation in di diesel engine using an improved soot model
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DOI：
10.1016/j.applthermaleng.2013.09.052
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发表时间：
2014-01
影响因子：
6.4
通讯作者：
Xiaobei Cheng;Liang Chen;G. Hong;Fangqin Yan;Shijun Dong
中科院分区：
文献类型：
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作者：
Xiaobei Cheng;Liang Chen;G. Hong;Fangqin Yan;Shijun Dong
微粒排放是柴油机燃烧过程中产生的最有害的污染物之一。预测碳烟形成的能力是优化发动机性能和最小化碳烟排放所需的关键要素之一。为了更好地模拟柴油机燃烧过程中碳烟形成的物理和化学过程，本文提出了一种唯象碳烟模型。该混合模型的特点是在碳烟氧化过程中考虑了湍流对化学反应速率的影响。碳烟的形成和氧化过程模拟与应用的混合方法，包括颗粒湍流传输控制速率和碳烟氧化速率。与原始碳烟模型相比，该混合模型预测的缸内压力、放热率和碳烟排放与试验结果吻合较好。利用验证后的混合模型研究了喷油提前角对发动机性能的影响。结果表明，新的碳烟模型预测合理的碳烟空间分布在燃烧室内。混合动力缸内高温区分布较广，碳烟和NOx排放与喷油开始时刻有关。延迟SOI定时增加了扩散燃烧的部分，并且随着燃料喷射定时的延迟，碳烟浓度显著增加。预测的碳烟浓度和颗粒质量的分布提供了一些新的见解在直喷式（DI）发动机碳烟的形成和氧化过程。混合唯象碳烟模型显示出更大的潜力，以提高对直喷式柴油机燃烧和碳烟形成过程的理解。
Particulate emission is one of the most deleterious pollutants generated by Diesel fuel combustion. The ability to predict soot formation is one of the key elements needed to optimize the engine performance and minimize soot emissions. This paper reports work on developing, a phenomenological soot model to better model the physical and chemical processes of soot formation in Diesel fuel combustion. This hybrid model features that the effect of turbulence on the chemical reaction rate was considered in soot oxidation. Soot formation and oxidation processes were modeled with the application of a hybrid method involving particle turbulent transport controlled rate and soot oxidation rate. Compared with the original soot model, the in-cylinder pressures, heat release rate and soot emissions predicted by this hybrid model agreed better with the experimental results. The verified hybrid model was used to investigate the effect of injection timing on engine performance. The results show that the new soot model predicted reasonable soot spatial profiles within the combustion chamber. The high temperature gas zone in cylinder for hybrid model case is distributed broadly soot and NOx emission dependence on the start-of-injection (SOI) timing. Retarded SOI timing increased the portion of diffusion combustion and the soot concentration increased significantly with retarding of the fuel injection timing. The predicted distributions of soot concentration and particle mass provide some new insights on the soot formation and oxidation processes in direct injection (DI) engines. The hybrid phenomenological soot model shows greater potential for enhancing understanding of combustion and soot formation processes in DI diesel engines.