Abstract A decoupling physical–chemical surrogate (DPCS) model was established for simulation of the spray and combustion characteristics of multi-component biodiesel fuels. In the DPCS model, the physical and chemical properties of biodiesel fuels are described separately. For the case study of soybean methyl ester (SME), the physical properties are represented based on the five primary components, i.e., methyl palmitate, methyl stearate, methyl oleate, methyl linoleate, and methyl linoleate. Meanwhile, the chemical kinetics of SME are described by a skeletal reaction mechanism composed of methyl decanoate, methyl 5-decenoate, and n-decane. Furthermore, an improved quasi-dimensional multi-component vaporization model was applied to predict the fuel vaporization process. To validate the DPCS model, the predictions from the present model and the previous models are compared with the experimental data, including the liquid penetration in a constant-volume bomb and the combustion and emission characteristics in a premixed charge compression ignition (PCCI) engine. The results indicate that the predictions of the DPCS model agree better with the measurements than the previous models considering only the single-component physical and/or single-component chemical properties of SME on the spray, ignition, and combustion behaviors. It is found that the ignition delay and heat release rate of PCCI combustion are dominated by the evaporation rate of SME and the fuel-reactivity stratification within the cylinder. By considering the multi-component properties of SME, the combustion and emission characteristics can be satisfactorily reproduced by the DPCS model. Meanwhile, the computational time can be well controlled due to the simplification of the physical and chemical surrogate sub-models.

中文翻译：

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开发用于模拟多组分生物柴油燃料的喷雾和燃烧的解耦物理-化学替代 (DPCS) 模型

摘要 建立了一种解耦物理化学替代物（DPCS）模型，用于模拟多组分生物柴油燃料的喷雾和燃烧特性。在 DPCS 模型中，生物柴油燃料的物理和化学特性是单独描述的。对于大豆甲酯 (SME) 的案例研究，物理性质基于五种主要成分表示，即棕榈酸甲酯、硬脂酸甲酯、油酸甲酯、亚油酸甲酯和亚油酸甲酯。同时，SME 的化学动力学通过由癸酸甲酯、5-癸烯酸甲酯和正癸烷组成的骨架反应机制来描述。此外，改进的准维多组分汽化模型被应用于预测燃料汽化过程。为了验证 DPCS 模型，将当前模型和先前模型的预测与实验数据进行了比较，包括定容弹中的液体渗透以及预混装料压缩点火 (PCCI) 发动机中的燃烧和排放特性。结果表明，仅考虑 SME 在喷雾、点火和燃烧行为方面的单组分物理和/或单组分化学性质，DPCS 模型的预测与测量结果的一致性优于之前的模型。发现PCCI燃烧的点火延迟和放热速率受SME蒸发速率和气缸内燃料反应分层的支配。通过考虑 SME 的多组分特性，DPCS模型可以令人满意地再现燃烧和排放特性。同时，由于物理和化学替代子模型的简化，可以很好地控制计算时间。