Interfacial phenomena of coolant contacting with superhot surface

本文从实验和理论两方面研究了1999 - 2000财政年度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。重点放在理解水滴与表面碰撞后的反冲和反弹/破裂过程上。已证实水滴与热表面碰撞的行为强烈依赖于韦伯数（=We）。当We数较小时，液滴撞击热表面呈扁平圆盘状扩散并达到最大直径。此后，液滴中心区域和中心部分的膨胀过程继续向上拉长。最后，液滴从表面反弹成保龄球形。对于较大的We数，已经发现液滴会分裂成一些部分。此外，还发现存在第一临界韦伯数We_< < < < < < < < < < < < < < < < < < < < < < < < < < < < < > > > > > > > > > > > > > > > > > > > >此外，还对液滴的崩解机理进行了实验研究。在扩散/反冲过程中，液滴崩解发生在We_<cri1>以上的We数范围内。随着韦伯数的增加，液滴的变形规模增大，外围区域环状结构的截面积趋于小而不均匀。因此，We_<cri1>，环形结构的转速差异局部发生在周向。根据We数，发现液滴解体过程可分为两种类型。当We数较低，但在We_<cri1>以上时，液滴在反冲过程中分裂成若干部分。但是。在第2韦伯数We_<cri2>以上，液滴在扩散过程中发生崩解，崩解液滴向外移动较远。本研究获得的一系列结果在国际期刊上以大量论文的形式报道。再次，撰写了一份科学研究资助项目的研究报告，并将研究结果报告给教育部。因此，可以参考这份报告来检查结果。少

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