SINTEF Ocean, Environment Technology, Trondheim, Norway.
Hawaii Natural Energy Institute, School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, HI, USA.
Mar Pollut Bull. 2019 Jun;143:256-263. doi: 10.1016/j.marpolbul.2019.04.012. Epub 2019 Apr 30.
The degree to which droplet shedding (tip-streaming) can modify the size of rising oil droplets has been a topic of growing interest in relation to subsea dispersant injection. We present an experimental and numerical approach predicting oil droplet shedding, covering a wide range of viscosities and interfacial tensions. Shedding was observed within a specific range of droplet sizes when the oil viscosity is sufficiently high and the IFT is sufficiently low. The affected droplets are observed to reduce in size, as smaller satellite droplets are shed, until the parent droplet reaches a stable size. Shedding of smaller droplets is related to the viscosity-dominated modified capillary number (Ca'), especially for low dispersant dosages recommended for subsea dispersant injection. This, in combination with the IFT-dominated Weber number (We), characterise droplets into three possible states: 1) stable (Ca' < 0.21 &We<12); 2) tip-streaming (Ca' > 0.21 &We<12); 3) unstable and subject to total breakup (We>12).
液滴（射流）脱落在多大程度上可以改变上升油滴的大小，这是与海底分散剂注入相关的一个日益受到关注的话题。我们提出了一种实验和数值方法来预测油滴的脱落，涵盖了广泛的粘度和界面张力范围。当油的粘度足够高且界面张力足够低时，在特定的液滴尺寸范围内观察到液滴脱落。脱落的液滴会变小，因为较小的卫星液滴会脱落，直到母液滴达到稳定的大小。较小液滴的脱落与粘度主导的修正毛细数（Ca'）有关，特别是对于海底分散剂注入推荐的低分散剂量。这与界面张力主导的韦伯数（We）相结合，将液滴分为三种可能的状态：1）稳定（Ca' < 0.21 和 We < 12）；2）射流（Ca' > 0.21 和 We < 12）；3）不稳定并可能完全破裂（We > 12）。
