氧气与煤油的气液对撞式喷油雾化是连续旋转爆轰发动机(Continuously Rotating Detonation Engine,CRDE)可燃混合物供给的核心技术,喷油雾化特性是CRDE点火和燃烧稳定性的关键,但此特性尚不清楚.通过将欧拉多相流模型(Volume of Fluid,VOF)和拉格朗日离散液滴模型(Discrete Phase Model,DPM)耦合的方法,采用VOF方法直接求解较大的液体团块,采用DPM方法追踪小液滴颗粒,以实现从喷嘴内流、喷雾近场到喷雾远场的多尺度耦合,进而在耦合了喷嘴内部流动的影响下探究煤油射流在氧气射流不同流速、不同撞击角度情况下的一次雾化(破碎形态和发展轨迹)和二次雾化过程(煤油液滴的索特平均直径SMD).基于动态网格自适应,精准捕捉到了煤油射流在氧气射流撞击下的雾化破碎过程和喷雾粒径分布特性.数值模拟研究表明,射流破碎过程中主要发生的是液柱破碎和表面剪切破碎,气体来流速度对液柱破碎的影响较大,撞击角度对液滴数量和平均粒径影响较大.
Numerical simulation of gas-liquid impinging atomization and breakup of continuous rotating detonation engine based on VOF-DPM method
The atomization of oxygen and liquid phase fuel by gas-liquid collision injection is the core technology of Continuously Rotating Detonation Engine(CRDE)combustible mixture supply.The atomization characteristic of fuel injection in this technology is the key to the ignition and combustion stability of CRDE,but this characteristic is still unclear.By coupling the VOF(Volume of Fluid)Euler multiphase flow model with the DPM(Discrete Phase Model)Lagrangian discrete droplet model.The VOF method is used to directly solve the large liquid mass,while the DPM method is used to track the small droplet particles,so as to realize the multi-scale coupling from the nozzle flow and the near field spray to the far field spray.Then,under the influence of coupling the flow inside the nozzle,the primary atomization(crushing form and development track)and secondary atomization process(Sotter mean diameter of kerosene droplets)of the oxygen jet under the condition of different flow rates and different impact angles are explored.Based on dynamic mesh adaptation,the atomization and crushing process of kerosene jet under the impact of oxygen jet and the characteristics of spray particle size distribution are accurately captured.Numerical simulation shows that liquid column breakage and surface shear breakage mainly occur in the process of jet breakage.The gas flow velocity has a great influence on the liquid column breakage,and the impact angle has a great influence on the number and average particle size of droplets.
万方数据
维普
