论文标题
液滴碰撞的关键费用
Critical charges for droplet collisions
论文作者
论文摘要
空气中未充电的微米大小的水滴的碰撞效率取决于在平均无路径的液滴分离，van-der-waals力量或两者的组合下的流体动力学分解。相反，如果电荷足够大，静电力决定了带电液滴的碰撞效率。为了找到向电荷主导碰撞过渡的电荷，我们计算了在静止空气中沉降的带电的，流体动力相互作用的液滴的碰撞效率，包括在小界面距离下流体动力学的分解。对于相对带电的液滴，当相对液滴动力学的鞍点退出流体动力学分解的区域时，发生过渡。对于Radii $ 16 \，μ$ m和$ 20 \，μ$ m的液滴，这发生在$ \ sim 10^3 $基本费用$ e $。对于较小的电荷，碰撞效率取决于kN的数量（定义为空气平均值路径与平均液滴半径的比率），而对于较大的电荷而言，则没有。对于带有相同极性的液滴，关键充电为$ \ sim 10^4 \，E $对于上述半径。
The collision efficiency of uncharged micron-sized water droplets in air is determined by the breakdown of hydrodynamics at droplet separations of the order of the mean-free path, by van-der-Waals forces, or a combination of the two. In contrast, electrostatic forces determine the collision efficiency of charged droplets if the charge is large enough. To find the charge for which the transition to charge-dominated collisions occurs, we computed the collision efficiency of charged, hydrodynamically-interacting droplets settling in quiescent air, including the breakdown of hydrodynamics at small interfacial distances. For oppositely charged droplets, the transition occurs when a saddle point of the relative droplet-dynamics exits the region where the hydrodynamics breaks down. For droplets with radii $16\,μ$m and $20\,μ$m, this occurs at $\sim 10^3$ elementary charges $e$. For smaller charges, the collision efficiency depends upon the Kn number (defined as the ratio of the mean-free-path of air to the mean droplet radius), whereas for larger charges it does not. For droplets charged with the same polarity, the critical charge is $\sim 10^4\,e$ for the above radii.
