Numerical Investigation of Breakup Law and Scaling Criterion of Supercooled Large Droplet

Abnormal icing caused by the supercooled large droplet (SLD) seriously endangers the flight safety. Due to the larger size of SLD, droplet breakage usually occurs during the motion of SLD. To investigate the breakup law of SLD, the motion of SLD in the wind tunnel was simulated. Results indicated that relative velocity and droplet diameter are two important factors affecting the droplet breakage. The droplet with larger diameter is more prone to break up while the droplet with larger relative velocity is generally broken at the upstream of the wind tunnel. When the peak We number at the stable section is greater than 12.49, the bagged breakup occurs in the stable section. When the peak We number at the contraction section is greater than 4.38, the oscillatory breakup occurs in the contraction section. A new scaling criterion B-criterion considering the SLD breakage was proposed. Combined the Ruff method with scaling criterion, it can be found that the comprehensive quantitative index of B+Ruff method is 13.6% and 7.3% lower than that of pi b+Ruff method and Wed+Ruff method, respectively.