【摘要】 为了研究超高压喷射条件下缸内非常态燃油的雾化特性,分析非常态燃油各个物性参数与压力之间的关系;搭建可视化喷雾闪光摄影试验台架,在AVL FIRE平台上对喷雾过程进行三维数值仿真;利用喷雾发展的试验结果验证仿真模型的准确性,并研究喷射背压、喷孔直径对燃油雾化特性的影响。研究结果表明:在超高压喷射条件下,燃油密度、音速和弹性模量的增大有利于油滴在喷嘴出口处获得较大的湍动能,进一步提高燃油的雾化质量;喷射背压增大时油束与缸内空气之间的能量交换加剧,射流扰动增强,加剧了油滴的二次破碎;随着喷孔直径增大,油束的初始湍动能增加,有助于气态燃油向燃烧室四周和底部扩散发展。更多还原

【Abstract】 In order to study the atomization characteristics of non-normal fuel in-cylinder under the condition of super-high pressure injection, the relationship between physical properties of non-normal fuel and pressure was analyzed.Visual spray flash photography test bench was set up. Three-dimensional numerical simulation of spraying process was completed on AVL FIRE software platform. The accuracy of the simulation model was verified by the experimental results of spray development. The influences of injection back pressures and nozzle diameters on atomization characteristics were studied. The results show that under the condition of super-high pressure injection, the increase of fuel density, sound velocity and elasticity modulus is good for the oil beams to obtain a better jet state at the outlet of nozzle, which further improves the quality of atomization. With the increase of injection back pressure, energy exchange between the oil beams and air becomes more intense, which enhances the jets disturbance and catalyzes the secondary broken of oil droplet. With the increase of nozzle diameter, initial turbulent kinetic energy of oil beams increases, which is helpful for the diffusion development of gaseous fuel to the surrounding and the bottom of combustion chamber.更多还原