【摘要】 目前,关于内燃机燃油喷雾的研究通常采用拉格朗日模型,欧拉模型则相对较少.本文利用构建的欧拉-拉格朗日模型对ECN喷雾实验进行数值模拟研究.结果显示,在150 MPa喷射压力下,喷嘴附近存在明显的连续欧拉液相.然而,在液核的下游,离散相液滴的破碎、碰撞、融合及聚集等均对界面面积密度、粒子直径的分布产生明显影响.由定量分析可知,在LES湍流模型下,除轴距6 mm附近的狭窄区间燃料体积分数存在较大偏差外,其对整个喷雾的空间分布以及粒径分布均实现了很好的预测.更多还原

【Abstract】 At present,Lagrangian models are usually adopted for studying fuel spray in an internal combustion engine,whereas studies based on Eulerian models were fewer.In this work,an Eulerian-Lagrangian model is established,and it is used to conduct numerical simulations of the engine combustion network(ECN) spray experiment.The results show that under an injection pressure of 150 MPa,a considerable amount of continuous Eulerian liquid phase exists near the nozzle.However,in the downstream of the liquid core,the fragmentation,collision,fusion and aggregation of discrete droplets exert a significant effect on the distributions of interfacial area density and droplet diameter.Through quantitative analysis,it is found that the spatial distribution in the whole spray process and the distribution of droplet diameters are well predicted using the large-eddy simulation(LES) turbulence model,except that some relatively large deviations of fuel volume fraction appear in a narrow range 6 mm away from the axis.更多还原