In this work, a hybrid breakup model tailored for direct-injection spark-ignition engine sprays is developed and implemented in the OpenFOAM CFD code. The model uses the Lagrangian–Eulerian approach whereby parcels of liquid fuel are injected into the computational domain. Atomization and breakup of the liquid parcels are described by two sub-models based on the breakup mechanisms reported in the literature. Evaluation of the model has been carried out by comparing large-eddy simulation results with experimental measurements under multiple direct-injection spark-ignition engine-like conditions. Spray characteristics including liquid and vapor penetration curves, droplet velocities, and Sauter mean diameter distributions are examined in detail. The model has been found to perform well for the spray conditions considered in this work. Results also show that after the end of injection, most of the residual droplets that are still in the breakup process are driven by the bag and bag–stamen breakup mechanisms. Finally, an effort to unify the breakup length parameter is made, and the given value is tested under various ambient density and temperature conditions. The predicted trends follow the measured data closely for the penetration rates, even though the model is not specifically tuned for individual cases.

中文翻译：

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具有集成雾化/分解模型的直喷式火花点火发动机类条件下的大涡喷雾模拟

在这项工作中，开发了一种为直喷火花点火发动机喷雾量身定制的混合分解模型，并在 OpenFOAM CFD 代码中实现。该模型使用拉格朗日-欧拉方法，将液体燃料块注入计算域。基于文献中报道的破碎机制，液体包裹的雾化和破碎由两个子模型描述。该模型的评估是通过将大涡模拟结果与多次直喷火花点火发动机类似条件下的实验测量结果进行比较来进行的。喷雾特性包括液体和蒸汽渗透曲线、液滴速度和 Sauter 平均直径分布被详细检查。已发现该模型在本工作中考虑的喷雾条件下表现良好。结果还表明，注射结束后，大部分仍在破碎过程中的残留液滴是由袋和袋-雄蕊破碎机制驱动的。最后，努力统一破碎长度参数，并在各种环境密度和温度条件下测试给定值。预测趋势与渗透率的测量数据密切相关，即使该模型并未针对个别情况进行专门调整。