不同液滴破碎模型的验证及柴油机在燃气混合过程中的应用

在射流不稳定性理论的基础上,将喷嘴内部的湍流流动以权重的形式加入初次破碎模型中；根据液滴的变形量采用TAB与KH-RT模型竞争的机制来计算液滴二次破碎；建立了Hybrid液滴破碎的数学模型。通过与实验数据、TAB和KH-RT破碎模型的计算结果对比,验证模型计算的准确性。Hybrid模型计算的液滴碰壁后飞溅半径和高度的最大相对误差分别为8%和6%,远小于其他两个模型的最大相对误差值。将验证过的三个破碎模型应用于柴油机中,比较了三个破碎模型对燃油分布的影响。研究发现,Hybrid模型的计算结果较比TAB和KH-RT模型准确度更高。 

Evaluation of different breakup models and application to the mixture preparation process for diesel engines

On the basis of the theory of jet instability, the turbulent flow inside the nozzle was added into the primary breakup model in the form of weight coefficient.According to the value of deformation of the droplet, the TAB model and the KH-RT model were used to calculate the droplet breakup process by competition mechanism, and then the mathematical model of breakup. The accuracy of the model was verified by comparing the calculated results with the experimental data, TAB and KH-RT breakup model. The maximum relative errors of the Hybrid breakup model for the calculation of the radius and height after impingement were 8% and 6%, respectively, which were far less than the calculated values of the other two breakup models. The three breakup models were applied to the diesel engine, and the effects of these models on the fuel distribution were compared. The study found that the calculation result of the Hybrid breakup model was more accurate than the TAB and KH-RT model.