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Interfacial phenomena of coolant contacting with superhot surface

冷却液与过热表面接触的界面现象

基本信息

批准号：
11450274
负责人：
HATTA Natsao
金额：
$ 2.3万
依托单位：
Nippon Bunri University (2000)Kyoto University (1999)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11450274/
关键词：
Hot wetallic surface Leidenfrost point Wething Pheaomenon Solid liguid Interface Vapor filw Boiling Weber number Black Zone ウェーバー数数値解析自由表面レイノルズ数スプレー冷却熱伝達固液接触

项目摘要

The collision dynamics of a water droplet impinging on solid surfaces above the Leidenfrost temperature have been investigated, during the period of fiscal 1999 to 2000, from an experimental and theoretical point of view. Emphasis has been placed upon understanding the recoiling, and rebounding/breaking-up processes of a water droplet after collision with surfaces. The behavior of a water droplet colliding with hot surface has been confirmed to strongly depend on the Weber number (=We). For a small We number, the droplet impinging on the hot surface spreads in the shape of a flattened disk and reaches a maximum diameter. Thereafter, the swelling process in the central region and center part of the liquid drop continues to elongate upwards. Finally, the liquid drop rebounds as a bowling-pin shaped mass from the surface. For a larger We number, the droplet has been found to break up into some parts. Also, it has been found that there is the first critical Weber number We_<cril> whether o … More f not the droplet is disintegrated into some parts. Furthermore, the droplet disintegration mechanism has been examined experimentally. The droplet disintegration occurs in the We number range above We_<cri1> in the spreading/recoiling process. With increasing the Weber number, the deformation scale of the droplet is enlarged and the sectional area of the ring structure in the peripheral region tends to be small and ununiform. Hence We_<cri1> the difference in the rotational velocity of the ring structure occurs locally in the circumferential direction. The droplet disintegration process has been found to be divided into two types according to the We number. For the case of low We number, but above We_<cri1> the droplet breaks up into some parts in the recoiling process. But. above the 2-nd Weber number We_<cri2> the droplet disintegration occurs in the spreading process and disintegrated drops move far away outorwards.A series of results obtained in the present in the present investigation were reported in the international journals as a lot of papers. Again, A report of the research performed by Grant-In-Aid for scientific research was written to report the results obtained to The Ministry of Education. Therefore, one can refer to this report for inspecting the results. Less

在1999 - 2000财政年度期间，从实验和理论的角度出发，研究了水滴在莱顿弗罗斯特温度以上的固体表面上的碰撞动力学。重点放在了解反冲，反弹/破碎的水滴与表面碰撞后的过程。水滴与热表面碰撞的行为已被证实强烈依赖于韦伯数（=We）。对于一个小的We数，液滴撞击在热表面上扩展的扁平盘的形状，并达到最大直径。此后，液滴的中心区域和中心部分的溶胀过程继续向上伸长。最后，液滴从表面反弹为保龄球针形状的物质。对于较大的We数，已经发现液滴分裂成一些部分。此外，还发现存在第一个临界韦伯数We_<cril>（？） ...更多信息如果液滴没有被分解成一些部分。此外，液滴破碎机制已被实验研究。在扩散/反冲过程中，液滴在We_2以上的We_2数范围内发生解体<cri1>。随着Weber数的增加，液滴的变形尺度增大，且在外围区域形成的环状结构截面积变小且不均匀。因此，<cri1>环结构的旋转速度的差异局部地发生在周向方向上。根据We数，液滴的破碎过程可以分为两种类型。对于低We数但高于We_的情况，<cri1>液滴在反冲过程中破碎成一些部分。但是...在第二韦伯数W_e以上，<cri2>液滴在铺展过程中发生解体，解体后的液滴向外运动，目前所获得的一系列结果已在国际上发表了大量论文。此外，还编写了一份科学研究补助金进行的研究报告，向教育部报告所取得的成果。因此，可以参考本报告检查结果。少