基于线性涡模型和化学反应计算加速方法的喷雾燃烧的数值模拟研究

对燃油喷雾燃烧过程的认识及准确地预测对达到内燃机高效、清洁燃烧起着至关重要的作用。本项目采用大涡模拟（LES）结合化学反应动力学模型对湍流与喷雾燃烧过程进行详细的数值研究，同时以可视化实验数据为依据对结果进行验证。采用亚网格非黏性动态结构模型及液滴破碎雾化模型，研究小尺度湍流扰动及弥撒作用对液滴的运动，液滴破碎及蒸发过程的影响。基于线性涡亚网格燃烧模型开展小尺度湍流扰动对液体燃料雾化燃烧及排放过程的影响研究，揭示小尺度湍流与化学反应的相互作用，同时研究湍流对局部着火模式的影响。燃烧化学反应与LES耦合，会产生计算量过大的问题，本项目将采用动态自适应化学反应方法（DAC）和动态自适应建表方法（ISAT）深入研究其在喷雾燃烧过程中计算效率和精度并对其进行优化改进。本项目为实际发动机喷雾燃烧过程的研究提供了重要的理论基础和技术支持，同时对多相流，流体力学及内燃机喷雾燃烧学的发展有重要的学术价值。

It is important to understand the liquid spray and combustion process and accurately predict the spray combustion, which plays significant effects on the study of high-efficiency and clean combustion in internal combustion engine (ICE). This proposal will detailed explore the interactions of spray combustion and turbulence using large eddy simulation(LES) and detailed chemistry kinetic mechanism, and the simulation results will be validated by the visualized experimental data. Based on the non-viscosity sub-grid model and atomization models, the influences of small scale turbulence or turbulence fluctuation and turbulent dispersion velocity on the droplet motion, breakup and evaporation process will be investigated. This proposal will focus on the influence of small scale turbulence on the spray combustion and emissions using linear eddy model (LEM), which will reveal the interaction of turbulence and chemistry reaction. Meanwhile, the influence of turbulence on the local combustion modes also will be considered. Because the detailed chemistry kinetic mechanism coupled with LES will induce to large computation cost, this proposal will employ the dynamic adaptive chemistry (DAC) and in situ adaptive tabulation (ISAT) to investigate and improve the computational efficiency and accuracy in spray combustion. This proposal will provide the important theoretical basis and technical support for the spray and combustion process in the realistic internal combustion engine. In addition, the proposal will make contributions to the academic values of multi-phase fluid, fluid dynamics and spray combustion in ICE.