Interfacial phenomena of coolant contacting with superhot surface

从实验和理论的角度研究了1999-2000财政年度水滴撞击莱登弗罗斯特温度以上固体表面的碰撞动力学。重点是了解水滴与表面碰撞后的反冲和反弹/破碎过程。已经证实，水滴与热表面的碰撞行为强烈地依赖于韦伯数(=We)。对于较小的We数，撞击在热表面上的液滴以扁平的圆盘形状传播，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延伸。最后，液滴从表面反弹成保龄球针形状的团块。对于更大的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，它是否为…如果液滴不是分解成某些部分，那就更多了。此外，还对液滴的崩解机理进行了实验研究。在展开/反冲过程中，液滴的解体发生在We数以上的区域。随着韦伯数的增加，液滴的变形规模增大，环状结构在外围区域的截面积趋于小而不均匀。因此，环形结构的自转速度的差异在圆周方向上是局部存在的。根据WE数，液滴的崩解过程分为两种类型。对于较低的We数，但在We_&lt；Cri1；以上的情况下，液滴在后退过程中分解成一些部分。但。在第二个Weber数以上，液滴在扩散过程中发生解体，分解后的液滴向外移动很远。同样，编写了一份由科学研究补助金进行的研究报告，将所获得的结果报告给教育部。因此，可以参考这份报告来检查结果。较少

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