Fundamental Understanding of Cavitation Phenomenon

对空化现象的基本理解

• 批准号: 06402054
• 负责人: KATO Hiroharu
• 金额: $ 23.23万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06402054/
• 关键词: cavitation; viscous effect; temperature; vaporization; heat and mass transfer; cloud; re-entrant jet; burst; 熱伝達; 物質伝達; 熱的影響; 高温水; 実験; 数値計算; ナビエ・ストークスの式; 理論

This research has been made to understand cavitation phenomenon more deeply, focusing on (a) relation between cavitation and viscous flow, and (b) thermodynamic effect and internal flow of cavity.Observation and detailed measurement of flow field were made on developed sheet cavitation of a 2D foil section. Following conclusions were obtained :1. The sheet cavity was classified into two types whether the separated boundary layr around the cavity bursted or not. Accordingly, the cavity model for numerical analysis should be different.2. It was confirmed that generation of cloud cavitation was caused by re-entrant jet, which flowed upstream on the foil surface. Therefore, the generation of cloud cavitation could be prevented by a small obstacle such as fence or ditch on the foil surface.A small cavitation tunnel for high-temperature water (up to 140 deg.) was newly constructed and tested. The results were summarized as follows :1. The maximum temperature depression was about 1.4 degree in a developed sheet cavity at 140 degrees and 14 m/s of main flow. The depression was increased when the upstream boundary layr became thicker by manipuration.2. The prediction using Z-factor which was proposed by Kato (1984), agreed with experimental result.

本研究旨在更深入地了解空化现象，重点关注（a）空化与粘性流之间的关系，以及（b）热力学效应与空腔内部流动。对二维箔片截面的片状空化进行了流场观察和详细测量。得到以下结论： 1．无论空腔周围分离边界层是否破裂，板空腔分为两种类型。相应地，数值分析的空腔模型也应有所不同。 2．确认了云空化的产生是由在箔表面向上游流动的折返射流引起的。因此，可以通过箔表面的栅栏或沟渠等小障碍物来阻止云空化的产生。新建并测试了用于高温水（高达140℃）的小型空化隧道。研究结果如下： 1．在 140 度和 14 m/s 主流流速下，开发的片材腔体中的最大温降约为 1.4 度。当上游边界层因人工操作而变厚时，凹陷度增大。2． Kato（1984）提出的使用Z因子的预测与实验结果一致。

项目成果

H.Kato: Advances in Marine Hydrodynamics, Chapter 5 Cavitation. M.Ohkusu, Computation Mechanics Publications, Southampton, U.K., 233-277 (1996)

H.Kato：海洋流体动力学进展，第 5 章空化。

H.Kato,H.Kayano & Y.Kageyama: "A Consideration of Thermal Effect on Cavitation Bubble Growth" Cavitation and Multiphase Flow 1994,ASME. FED-194. 7-14 (1994)

加藤H、茅野H

H.Kato,M.Maeda,H.Kamono: "Temperature Depression in Cavity" Fluids Engineering Division Conference, ASME. FED-236. 407-413 (1996)

H.Kato、M.Maeda、H.Kamono：“腔内温度降低”流体工程分部会议，ASME。

H.Yamaguchi, H.Kato, N.Takasugi, H.Shigemitu, M.Harada: "Study of Cavitation on a Finite Span Foil with Sweptback Platform" International Symposium on Cavitation, Deauville, France. 367-372 (1995)

H.Yamaguchi、H.Kato、N.Takasugi、H.Shigemitu、M.Harada：“带有后掠平台的有限跨度箔上的空化研究”国际空化研讨会，法国多维尔。

M.Maeda, H.Kamono, H.Kato, H.Yamaguchi: "Temperature Measurements in Cavity in a High-Temperature Cavitation Tunnel" 8th Symp. on Cavitation, Kyoto. 133-136 (1995)

M.Maeda、H.Kamono、H.Kato、H.Yamaguchi：“高温空化隧道空腔中的温度测量”第 8 号症状。