Development of a new quantitative kinetic model for the analysis of heating and evaporation processes in complex hydrocarbon fuel droplets

本文提出了一种新的定量动力学模型，用于分析碳氢燃料液滴的加热和蒸发，适用于实际工程应用。该项目的工作将主要集中在以下两个方面。首先，本文提出了一种新的模拟复杂碳氢化合物分子的分子动力学算法，并重点研究了柴油燃料的近似模型--液体正十二烷（C_12H_26）的蒸发过程。正十二烷分子的复杂性将基于考虑许多假原子，每个假原子代表甲基（CH_3）或亚甲基（CH_2）基团而降低。这项研究将使我们能够了解这些分子的蒸发过程的基本物理学，并在与柴油发动机相关的广泛温度范围内估计正十二烷的蒸发/冷凝系数的值。第二，将发展一种新的数值算法，以解决玻尔兹曼方程，考虑到复杂分子之间的非弹性碰撞。在该算法中，涉及非弹性碰撞的额外维度将与描述分子整体平移运动的其他三个维度一起考虑。碰撞前后的总能量守恒将被考虑在内。对应于碰撞后分子的平移运动和内部运动分量的能量值的离散数量的组合将是允许的，并且这些组合的实现概率将是相等的。结果将被应用到动力学模拟的正十二烷液滴的蒸发过程中的柴油发动机一样的条件。这将是一个合作项目，曹炳阳博士（清华大学，北京，中国）。中国），其专长包括分子动力学模拟数值算法的开发，（俄罗斯莫斯科动力工程学院），其专业知识主要集中在波尔兹曼方程的数值代码的开发，PI，Sergei Sazhin教授，他的专长包括开发燃料液滴加热和蒸发的新物理模型，该项目的共同研究员Morgan Heikal教授将为项目成员提供关于模型与汽车应用的相关性的建议，以及一名研究生，他将接受新研究方法的培训，这些方法在英国并不广为人知和/或使用。该项目将建立在以前资助的EPSRC项目EP/C527089/1和EP/E02243 X/1以及皇家学会与俄罗斯的联合项目的基础上，支持PI和I博士之间的合作。希什科娃

This proposal is concerned with the development of a new quantitative kinetic model for the analysis of hydrocarbon fuel droplet heating and evaporation, suitable for practical engineering applications. The work on the project will be mainly focused on the following two areas. Firstly, a new molecular dynamics algorithm for the simulation of complex hydrocarbon molecules, with particular focus on the evaporation process of liquid n-dodecane (C_12H_26), which is used as an approximation for Diesel fuel, will be developed. The complexity of the n-dodecane molecules will be reduced based on the consideration of a number of psuedoatoms, each representing the methyl (CH_3) or methylene (CH_2) groups. This research will allow us to understand the underlying physics of the evaporation process of these molecules and to estimate the values of the evaporation/ condensation coefficient of n-dodecane in a wide range of temperatures relevant to Diesel engines. Secondly, a new numerical algorithm for the solution of the Boltzmann equation, taking into account inelastic collisions between complex molecules, will be developed. In this algorithm, additional dimensions referring to inelastic collisions will be taken into account alongside three other dimensions describing the translational motion of molecules as a whole. The conservation of the total energy before and after collisions will be taken into account. A discrete number of combinations of the values of energy corresponding to the components of translational motions and internal motions of molecules after collisions will be allowed and the probabilities of the realisation of these combinations will be equal. The results will be applied to the kinetic modelling of the evaporation process of n-dodecane droplets in Diesel engine-like conditions. This will be a collaborative project between Dr Bing-Yang Cao (Tsinghua University, Beijing, P.R. China), whose expertise includes the development of numerical algorithms for molecular dynamics simulation, Dr Irina Shishkova (Moscow Power Engineering Institute, Russia), whose expertise is focused on the development of numerical codes for the solution of the Boltzmann equation, the PI, Professor Sergei Sazhin, whose expertise includes the development of new physical models of fuel droplet heating and evaporation with a view of applications to modelling the processes in internal combustion engines, Professor Morgan Heikal, the co-investigator of the project, who will advise the project members on the relevance of the models to automotive applications, and a research student, who will be trained in new research methods, not widely known and/or used in the UK. This project will build upon previously funded EPSRC projects EP/C527089/1 and EP/E02243X/1, and the Royal Society Joint project with Russia, supporting the collaboration between the PI and Dr I. Shishkova.