What Determines the Drop Size in Sprays?
What Determines the Drop Size in Sprays?
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DOI：
10.1103/physrevx.8.031019
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发表时间：
2018-07-20
影响因子：
12.5
通讯作者：
Bonn, Daniel
中科院分区：
文献类型：
--
作者：
Kooij, Stefan;Skis, Rick;Bonn, Daniel
在许多情况下，喷雾是由液体射流或液体片的破碎形成的。我们研究了决定片材破碎过程中特征液滴尺寸的不同参数。我们改变喷涂参数，例如喷嘴的压力和几何形状，以及流体参数，例如粘度和表面张力。综合结果表明，液滴尺寸是由流体惯性和表面张力之间的竞争决定的，这使得可以根据韦伯数和喷嘴的几何形状来预测液滴尺寸。一旦用平均液滴尺寸重新调整，尺寸分布可以通过具有两个参数 n 和 tn 的复合伽马分布来描述，前者设置韧带波纹，后者设置韧带尺寸分布的宽度。 m 的拟合值表明圆锥形喷嘴产生几乎相同尺寸的韧带，而扁平扇形喷嘴产生更广泛分布的韧带尺寸。 n 值表明，对于所有喷嘴，韧带都非常波纹，这对于此类喷雾形成过程来说并不意外。通过使用喷雾的高速摄影，可以直接测量参数 m 和 n，并且实际上控制了液滴尺寸分布。
In many instances, sprays are formed from the breakup of liquid jets or sheets. We investigate the different parameters that determine the characteristic drop size in the breakup of sheets. We vary both the spraying parameters, such as the pressure and geometry of the nozzle, and the fluid parameters, such as viscosity and surface tension. The combined results show that the drop size is determined by a competition between fluid inertia and surface tension, which allows for the prediction of the drop size from the Weber number and geometry of the nozzle. Once rescaled with the average drop size, the size distribution is found to be described by a compound gamma distribution with two parameters, n and tn, with the former setting the ligament corrugation and the latter the width of the ligament size distribution. Fit values for m indicate that nozzles of a conical type produce ligaments of almost equal size, while the flat fan nozzles produce broader distributed ligament sizes. Values for n show that, for all nozzles, ligaments are very corrugated, which is not unexpected for such spray formation processes. By using high-speed photography of the sprays, the parameters m and n can be directly measured and, indeed, govern the drop-size distribution.