Abstract We present a combined experimental-numerical study of the primary breakup of a single-phase attenuating liquid sheet emerging from a flat fan nozzle. An experimental setup has been built to produce flat fan liquid sheets/sprays at near industrial conditions, i.e. high pressure and turbulent. The process of sheet disintegration, for a transitional and a turbulent sheet, is visualized using high-speed shadowgraphy. The shadowgrams resolve features of the primary breakup at very fine spatial and temporal resolutions, revealing new information about attenuating liquid sheets. Three breakup mechanisms are identified in the central region of the sheet; two of these, aerodynamic instability and disruption by perforations, are well known. The third mechanism, bag breakup, appears not to have been previously reported in the context of flat fan sprays. Highly resolved Computational Fluid Dynamics (CFD) is employed to model the phenomena of sheet breakup. Features of the attenuating liquid sheet are computed and compared with experimental measurements where strong agreement is found. Breakup mechanisms similar to those observed experimentally are resolved in the CFD simulations, confirming the ability of the simulation methodology to extend studies to scales that are not achievable via laboratory experiments. The mechanisms of holes nucleation and growth are studied, we find that hole nucleation in a turbulent single-phase liquid sheet is due to the growth of local surface disturbance which is initiated by nozzle turbulence.

中文翻译：

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衰减液片破碎机理的实验与建模

摘要 我们提出了从扁平扇形喷嘴喷出的单相衰减液片的初级破裂的联合实验数值研究。已经建立了一个实验装置来在接近工业条件（即高压和湍流）下生产扁平扇形液体片/喷雾。片材分解过程，对于过渡片材和湍流片材，使用高速阴影成像进行可视化。阴影图以非常精细的空间和时间分辨率解析了一次破裂的特征，揭示了关于衰减液体层的新信息。在板材的中心区域确定了三种破碎机制；其中两个，空气动力学不稳定性和穿孔破坏是众所周知的。第三种机制，破袋，以前似乎没有在扇形喷雾的背景下报道过。高分辨率的计算流体动力学 (CFD) 被用于模拟板材破裂现象。计算衰减液体片的特征，并与发现强烈一致性的实验测量值进行比较。在 CFD 模拟中解决了类似于实验观察到的分解机制，证实了模拟方法将研究扩展到实验室实验无法实现的规模的能力。研究了孔洞的成核和生长机制，我们发现湍流单相液体片中孔洞的成核是由于喷嘴湍流引起的局部表面扰动的增长。高分辨率的计算流体动力学 (CFD) 被用于模拟板材破裂现象。计算衰减液体片的特征，并与发现强烈一致性的实验测量值进行比较。在 CFD 模拟中解决了类似于实验观察到的分解机制，证实了模拟方法将研究扩展到实验室实验无法实现的规模的能力。研究了孔洞的成核和生长机制，我们发现湍流单相液体片中孔洞的成核是由于喷嘴湍流引起的局部表面扰动的增长。高分辨率的计算流体动力学 (CFD) 被用于模拟板材破裂现象。计算衰减液体片的特征，并与发现强烈一致性的实验测量值进行比较。在 CFD 模拟中解决了类似于实验观察到的分解机制，证实了模拟方法将研究扩展到实验室实验无法实现的规模的能力。研究了孔洞的成核和生长机制，我们发现湍流单相液体片中孔洞的成核是由于喷嘴湍流引起的局部表面扰动的增长。在 CFD 模拟中解决了类似于实验观察到的分解机制，证实了模拟方法将研究扩展到实验室实验无法实现的规模的能力。研究了孔洞的成核和生长机制，我们发现湍流单相液体片中孔洞的成核是由于喷嘴湍流引起的局部表面扰动的增长。在 CFD 模拟中解决了类似于实验观察到的分解机制，证实了模拟方法将研究扩展到实验室实验无法实现的规模的能力。研究了孔洞的成核和生长机制，我们发现湍流单相液体片中孔洞的成核是由于喷嘴湍流引起的局部表面扰动的增长。