The development of gasoline spray at ultra-high injection pressures was analyzed using Large-Eddy simulation (LES). Two different nozzle hole geometries, divergent and convergent shape, were considered to inject the fuel at injection pressures ranging from 200 to 1500 bar inside a constant volume spray chamber maintained at atmospheric conditions. The discrete droplet phase was treated using a Lagrangian formulation together with the standard spray sub-models. The numerical results were calibrated by reproducing experimentally observed liquid penetration length and efforts were made to understand the influence of ultra-high injection pressures on the spray development. The calibrated model was then used to investigate the impact of ultra-high injection pressures on mean droplet size and droplet size distribution. In addition, the spray-induced large-scale eddies and entrainment rate were evaluated at different ultra-high injection pressures. Overall, simulation results showed a good agreement with available measurement data. At ultra-high injection pressures mean droplet sizes were significantly reduced and comprised very high velocities. Integral length scales of spray-induced turbulence and air entrainment rate into the spray were larger at higher injection pressure compared to lower ones.

中文翻译：

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汽油喷雾超高喷油压力的大涡模拟研究

使用大涡模拟 (LES) 分析了超高喷射压力下汽油喷雾的发展。两种不同的喷嘴孔几何形状，发散形状和会聚形状，被认为是在保持在大气条件下的恒定体积喷雾室内以 200 至 1500 巴的喷射压力喷射燃料。使用拉格朗日公式和标准喷雾子模型处理离散液滴相。通过再现实验观察到的液体渗透长度来校准数值结果，并努力了解超高注射压力对喷雾发展的影响。然后使用校准模型研究超高注射压力对平均液滴尺寸和液滴尺寸分布的影响。此外，在不同的超高注射压力下评估了喷雾引起的大规模涡流和夹带率。总体而言，模拟结果显示出与可用测量数据的良好一致性。在超高注射压力下，意味着液滴尺寸显着减小并具有非常高的速度。与较低的注射压力相比，在较高的注射压力下，喷雾引起的湍流和空气夹带率的整体长度尺度更大。