Development of the full Lagrangian approach for the analysis of vortex ring-like structures in disperse media: application to gasoline engines

由于两相混合物中的涡流环状结构存在于广泛的系统中，例如汽油发动机，因此这种过程的适当数学模型将允许工程师在对新技术进行昂贵的实验评估之前，快速测试优化和改进一系列工程系统的新方法。因此，这一建议涉及到一种被称为全拉格朗日方法（也称为奥西普索夫-拉格朗日方法）的数学方法的推广，使其能够模拟两相混合物中的涡环结构。该项目的主要重点是开发这种方法，使其能够在计算流体动力学（CFD）框架内对三维过程进行建模。该项目还将研究建立涡环状结构新数学模型的可能性，以考虑与某些工程应用相关的额外复杂性，例如椭圆核心的影响。这种多相流建模的新方法将结合目前正在进行的EPSRC项目EP/F069855/1开发的射流和液滴破裂模型。在适当的情况下，将新模型的预测结果与基于瞬态涡环形结构三维数值模拟的预测结果、基于传统研究CFD代码KIVA 3和商用CFD代码FLUENT的预测结果进行比较。本文还将基于离散相的全拉格朗日方法和载波相的涡旋方法的结合，对这些涡环形结构的建模进行可行性研究，以检验不同数学方法的优点和局限性。最后，数值和分析模型的预测将与在类似汽油发动机条件下获得的内部实验结果进行验证，从而评估使用模型表征汽油发动机过程的适用性。这将是一个合作项目，涉及外部顾问a . Osiptsov教授（俄罗斯罗蒙诺索夫莫斯科国立大学）和F. Kaplanski博士（爱沙尼亚塔林技术大学），他的专业知识主要集中在多相流和半解析涡旋环模型的全拉格朗日方法的发展。它将由S. Sazhin教授领导，他的专长包括开发用于内燃机建模的燃料液滴和喷雾过程的新物理模型。共同研究人员S. Begg博士和M. Heikal教授将就模型与汽车应用的相关性提出建议，并提供验证模型所需的实验数据。该项目将包括一名研究员。该项目将确保在先前资助的EPSRC项目EP/E047912/1中开发的物理和数学模型在质量上达到新的水平，支持PI，共同调查员和F. Kaplanski博士之间的合作，以及目前正在进行的项目EP/F069855/1。

As vortex ring-like structures in two-phase mixtures occur in a wide range of systems such as gasoline engines, appropriate mathematical models of such processes would allow engineers to rapidly test novel ways of optimising and improving a range of engineering systems before resorting to costly experimental evaluation of new technologies. This proposal is therefore concerned with the generalisation of a mathematical approach known as the full Lagrangian approach (also known as the Osiptsov-Lagrangian method) to enable it to model vortex ring-like structures in two-phase mixtures. The main focus of the project will be on the development of this approach to enable its use in the modelling of three-dimensional processes within a Computational Fluid Dynamics (CFD) framework. The project will also investigate the possibility of constructing new mathematical models of vortex ring-like structures, to take into account additional complications relevant to certain engineering applications such as the effect of an elliptical core. This new approach to the modelling of multiphase flows will incorporate the jet and droplet break-up models developed through a currently active EPSRC project EP/F069855/1. Where appropriate, predictions resulting from the new models will be compared with predictions based on three dimensional numerical simulations of transient vortex ring-like structures, based on the conventional research CFD code KIVA 3 and commercial CFD code FLUENT. A feasibility study will also be performed into the modelling of these vortex ring-like structures based on the combination of the full Lagrangian approach for the dispersed phase and the vortex method for the carrier phase to examine the advantages and limitations of the different mathematical approaches. Finally, predictions from numerical and analytical models will be validated against in-house experimental results obtained in gasoline engine-like conditions allowing an assessment to be made into the applicability of using the models for the characterisation of processes in gasoline engines.This will be a collaborative project involving external consultants Professor A. Osiptsov (Lomonosov Moscow State University, Russia) and Dr. F. Kaplanski (Tallinn Technical University, Estonia), whose expertise is mainly focused on the development of the full Lagrangian method for multiphase flows and semi-analytical vortex ring models. It will be led by Professor S. Sazhin, whose expertise includes the development of new physical models of fuel droplet and spray processes as applied to modelling internal-combustion engines. The co-investigators Dr. S. Begg and Professor M. Heikal will advise on the relevance of the models to automotive applications and provide the experimental data required for the validation of the models. A Research Fellow will be included in the project. This project will ensure a qualitatively new level of physical and mathematical models, developed in the previously funded EPSRC project EP/E047912/1, supporting the collaboration between the PI, co-investigators and Dr F. Kaplanski, and the currently active project EP/F069855/1.