Enhancement mechanism of impinging atomization by gas injection

Transactions of the Japan Society of Mechanical Engineers. B Pub Date : 2012-12-01 DOI:10.1299/KIKAIB.78.1990

C. Inoue, Toshinori Watanabe, T. Himeno, S. Uzawa

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引用次数: 1

Abstract

Impinging atomization, which has been widely utilized in liquid rocket propulsion systems, is able to produce fine drops at a rated operation. In contrast, however, the atomization characteristics deteriorate under off design conditions when injection velocity comes to be slower. In the present study, for improving atomization characteristics at off design operation, an effective technique is verified utilizing small amount of gas injection. The gas jet is supplied from a pressurized reservoir independent of the liquid supply system, and it is injected from the center of the liquid nozzles toward the impingement point. To clarify the flow field and the mechanism of the effectivity, experimental visualizations, drop size measurements and corresponding numerical analyses are carried out. It is elucidated that atomization is drastically promoted when the dynamic pressure of gas overcomes that of liquid at the impingement point. By the gas injection with the amount of only 1% of liquid mass flow rate, Sauter Mean Diameter (SMD) becomes one-tenth of the original SMD. In addition, the optimized atomization efficiency is achieved when the gas dynamic pressure is twice as much as the liquid at the impingement point.

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注气增强冲击雾化机理

碰撞雾化技术在液体火箭推进系统中得到了广泛的应用，它能够在额定运行下产生细小的液滴。相反，在非设计条件下，当喷射速度变慢时，雾化特性会恶化。在本研究中，为了改善非设计工况下的雾化特性，验证了利用少量注气的有效方法。气体射流由独立于供液系统的加压储层提供，并从液体喷嘴的中心向撞击点喷射。为了阐明流场和效果机理，进行了实验可视化、液滴尺寸测量和相应的数值分析。结果表明，当气体的动压超过液体的动压时，雾化效果显著提高。当注气量仅为液体质量流量的1%时，Sauter平均直径(SMD)变为原来SMD的十分之一。此外，当气体动压为碰撞点处液体动压的两倍时，雾化效率达到最优。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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Transactions of the Japan Society of Mechanical Engineers. B

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