气流中液化天然气液滴破碎数值模拟研究

Numerical simulation of liquified natural gas droplet breakup in gas phase flow

基于流体体积法和k-ε湍流模型对液化天然气单液滴在气流中的变形破碎情况进行模拟研究。研究不同We对液滴形态和破碎模式的影响,分析液滴形态变化过程中速度、加速度和阻力系数随时间的变化趋势,并研究不同流场下液滴变形破碎情况。结果表明,不同的We下,液滴呈现出不同的破碎模式,液滴发生剪切破碎的临界We为80左右,同一We下不同直径的液滴临界破碎时间有所不同;随着气液相对速度的We的增大,液滴的无量纲变形时间先递减后趋向于平缓;液滴变形破碎过程中,速度随着时间的延长而增加,加速度和阻力系数随着时间的延长先增后减;与普通流场相比,带挡板的流场中液滴变形破碎时间明显缩短。

The deformation and breakup of a single liquified natural gas droplet is simulated in gas phase flow by using the volume of fluid method and k-εturbulence model.The influence of We on droplet morphology and breakup mode was investigated,and the change tendencies of velocity,acceleration and drag coefficient with time during the process of droplet morphology change were studied.In addition,the droplet deformation and breakup in different flow fields were compared.The results indicate that the droplet shows different breakup modes in different We.The critical We of shear breakup is about 80,and the critical breakup time of different droplet diameter is different under the same We.With the increase in We at relative gas-liquid velocity,the curve of dimensionless deformation time of droplet decreases firstly and then tends to be flat.In the process of droplet deformation and breakup,the velocity keeps increasing,while the acceleration and drag coefficient increase firstly and then decrease with the increase in time.Compared with the original flow field,the deformation and breaking time of droplets in the flow field with baffle plates are significantly reduced.