Numerical Study of Deformation and Breakup Processes of Water Droplets in Air Flow

Abstract

Aimed at the problem that water droplets are easy to break up during the acceleration process in icing wind tunnel experiment, which makes it difficult for the particle size distribution of water droplets in the test section to conform to the icing weather conditions, the deformation and breakup regime of water droplets with a diameter of 100, 200, 400, 600, 800, 1 000 and 1 200 μm under the action of different air velocities(20, 50, and 80 m/s) are simulated by using the volume of fluid (VOF) method. The results show that under the action of 20 m/s air flow, the water droplet with a diameter of 600 μm does not break. Under the action of 50 m/s air flow, the water droplet with a diameter of 100 μm does not break. With the increase of Weber number, the wavelength of the most destructive wave also increases, and the breakup regime of water droplets changes from bag breakup to bag-plume breakup, to plume-shear breakup, and to shear breakup successively. The droplet breakup regime, including the bag breakup, bag/plume breakup, the plume/sheet-thinning breakup, and the shear breakup, has a significant effect on the ratio of the area of the largest droplet to the initial droplet. Under the condition that the initial drop diameter is the same, as the inlet velocity increases, the area ratio after breakup increases.

Keywords

• supercooled large drop (sld)
• deformation and breakup
• gas-liquid flow
• volume of fluid (vof) method