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A Study of Ultra-High Speed Liquid Flow Phenomena Using a Light Gas Gun

轻气枪超高速液体流动现象的研究

基本信息

批准号：
01550133
负责人：
TOMITA Yukio
金额：
$ 1.22万
依托单位：
Hokkaido University of Education (1990)Tohoku University (1989)
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01550133/
关键词：
Ultra-High Speed Liquid Flow Super-Cavity Splash Cavitation Bubble Droplet Shock Wave Water Jet Light Gas Gun ウォ-タ-ジェットキャビテ-ション気泡自由表面エロ-ジョンスプラッシュ速度計測

项目摘要

An experimental study was made of the problem concerned with the ultra-high speed liquid flow phenomena by means of a vertical from of light gas gun. First we conducted a preliminary experiment to obtain the relationship between powder mass and sabot flyer velocity. Using a 2g plastic sabot flyer, we obtained the flyer velocity ranging from several hundreds meters per second up to 2km/s. Based on the data obtained, we rushed a flyer from the above into water and observed the sequential surface phenomena such as the deformation of a free surface, the surface closure and the splash. We also observed the behavior of a cavity formed behind the substance moving into water. In the later stage of the substance movement, a cavity was fully developed and finally separated from the surface. Aftre the separation, an interesting phenomenon, a reentrant jet, occurred at the rear side of the closed cavity. It was flowing toward the substance. This kind of experiment was carried out for two test liqu … More ids, water and glycerin, in order to evaluate the liquid viscosity. Furthermore we found that cavitation bubbles generated during this process were strongly influenced by the adjacent cavity surface. In relation to this problem, an experimental study was made of a laser-produced bubble near a free surface. Consequently, we had some information about the bubble migration such that a free surface repels a bubble collapsing from the boundary. The behavior of two bubbles not only in phase but ou t of phase was also experimentally examined in detail.On the other hand, we investigated the problem of a pulsed water jet which belongs to be one of the typical examples of ultra-high speed liquid flow phenomena. A 1.15g plastic sabot, which has a ditch at its front side for carrying a little amount of water, impacts on a sabot stopper, thereafter theparated water goes ahead through a small hole inside the sabot stopper, like a nozzle, due to the inertia and finally impacts with the maximum velocity of 1.5km/s against a target which was set in the vacuum state. A pulsed jet emerging from the nozzle exit becomes unstable at the mixing layer, producing a large number of minute droplets. We observed a lot of microscpic erosion, so-called damage pit, on the surface of the target. They must be formed due to the high speed impacts of individual droplets. Less

利用轻气炮垂直流场对超高速液体流动现象进行了实验研究。首先，我们进行了初步的实验，以获得粉末质量和弹托飞片速度之间的关系。使用2g塑料弹托飞片，获得了几百米/秒到2km/s的飞片速度。根据所获得的数据，我们从上面冲到水中的飞片，并观察到连续的表面现象，如自由表面的变形，表面闭合和飞溅。我们还观察到物质进入水中后形成的空腔的行为。在物质运动的后期，空腔充分发展并最终与表面分离。分离后，在封闭腔的后侧出现了一个有趣的现象，即重入射流。它流向物质。对两种试验液进行了试验， ...更多信息 IDS、水和甘油，以评估液体粘度。此外，我们还发现在此过程中产生的空化气泡强烈的影响，相邻的空腔表面。针对这一问题，对激光在自由表面附近产生的气泡进行了实验研究。因此，我们有一些关于气泡迁移的信息，使得自由表面排斥从边界坍塌的气泡。另外，我们还研究了超高速液体流动现象中的一个典型例子--脉冲水射流问题。1.15g的塑料弹托前端有一个带少量水的沟槽，撞击弹托挡块后，分离出的水由于惯性通过弹托挡块内的小孔（如喷嘴）向前运动，最后以1.5km/s的最大速度撞击真空靶。从喷嘴出口出现的脉冲射流在混合层处变得不稳定，产生大量微小液滴。在靶表面观察到大量的微观侵蚀，即损伤坑。它们一定是由于单个液滴的高速撞击而形成的。少