Abstract Experimental testing on the unsteady aero-breakup of ethyl alcohol droplets was carried out at the rotating arm facility of INTA. The selection of the working fluid was driven by the need to explore wider ranges of the dimensionless parameters that govern the problem. A model airfoil was attached at the end of a 2.3 m long rotating arm driven by an electric motor. Droplets, whose diameter ranged from 500 μm to 1500 μm, were allow to fall in the path of the airfoil that attained velocities in the range between 30 m/s and 60 m/s. Droplets trajectories and breakup modes were recorded, and a new breakup mode was identified. Its sequence is as follows: 1) the droplet deforms as an oblate spheroid, 2) a bulge appears and grows on its flow facing surface, 3) the droplet thickens in the stream-wise direction; 4) the thickening in the rear part of the droplet develops in the shape of a cone, 5) the cone grows thinner until a finger like shape is formed. Additionally, based on a theoretical model developed by the authors, a comparison has been made between the deformation and breakup onset phases of ethyl-alcohol and water droplets up to the instant of breakup.

中文翻译：

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与非定常流动载荷相关的新液滴空气破碎机制

摘要 在INTA的旋转臂设备上进行了乙醇液滴非稳态空气破碎的实验测试。工作流体的选择是由于需要探索控制问题的更广泛的无量纲参数。一个模型翼型安装在一个由电动机驱动的 2.3 m 长旋转臂的末端。直径在 500 μm 到 1500 μm 之间的液滴被允许落在速度在 30 m/s 到 60 m/s 之间的翼型路径中。记录液滴轨迹和破碎模式，并确定了新的破碎模式。其顺序如下：1）液滴变形为扁球体，2）在其面向流动的表面上出现并生长凸起，3）液滴在流动方向上变稠；4) 液滴后部的增厚呈锥形发展， 5) 锥形变细直至形成手指状。此外，基于作者开发的理论模型，对乙醇和水滴直至破裂瞬间的变形和破裂起始阶段进行了比较。