气体中心式离心喷嘴喷雾实验与三维仿真

在实验的基础上, 基于RNG k-ε模型对常压下气体中心式同轴离心(gas-centered swirl coaxial，GCSC)喷嘴喷雾形态和破碎模式进行了三维仿真研究。采用网格自适应加密(adaptive mesh refinement，AMR)技术、耦合水平集和流体体积(coupled level-set and volume of fluid, CLSVOF)方法对气液界面进行捕捉。结果表明, 液体质量流率($\dot{m}_{\mathrm{l}}$)不变, 随着气体质量流率($\dot{m}_{\mathrm{g}}$)的增加, 中心气流的引射作用增强, 液膜内外压差增大, 雾化锥角减小, 并对其流动特性进行了分析; 而$\dot{m}_{\mathrm{g}}$不变时, 液膜在喷嘴出口的径向速度与切向速度随$\dot{m}_{\mathrm{l}}$的增大而增大, 导致雾化锥角增大。同时根据气液质量流率比(gas-liquid mass flow rate，GLR), 将喷雾的破碎模式分为穿孔破碎、气泡破碎和气动破碎。 

Experiment and Three-Dimensional Simulation of Gas-Centered Swirl Coaxial Injector Spray

On the basis of experiments at atmospheric pressure, a three-dimensional simulation study of the spray pattern and breakup mode of gas-centered swirl coaxial (GCSC) injector was conducted with the RNG k-ε model. The gas-liquid interface was captured by the adaptive mesh refinement (AMR) technique, coupled level-set and volume of fluid (CLSVOF) method. The results demonstrated that when the liquid mass flow rate ($\dot{m}_{\mathrm{l}}$) is constant, the ejection action of the central airflow is enhanced along with the gas mass flow rate ($\dot{m}_{\mathrm{g}}$). The internal and external pressure difference of the liquid film increases and the spray angle decreases. Meanwhile, the flow characteristics were analyzed. When $\dot{m}_{\mathrm{g}}$ is constant, the radial velocity and tangential velocity of the liquid film at the injector outlet increase with $\dot{m}_{\mathrm{l}}$, which may result in the increase of the spray angle. According to the gas-liquid mass flow rate (GLR), the breakup modes of spray are divided into the perforation breakup, bubble breakup and pneumatic breakup.