Exploitation of Hypervelocity liquid jet generator by using Neumann effect

高速液体射流已广泛应用于柴油机喷油工艺和水射流切割技术中。然而，它们的最高速度可达1公里/S。目前，无论是产生高速液体射流的方法还是其底流的技术都还没有很好的发展。以前，该项目的首席研究员开发了一种技术，即使用单级气炮，使1-2公里/S的平头高速弹丸撞击液体容器，产生3-4公里/S的高速射流。然而，这种方法需要非常精心设计的不可重复使用的喷嘴，因此永远不可能实用。众所周知，在火力工程中，反锥形装药一旦被引爆，就会产生沿其轴线的高速碎片喷流，其原理被称为冯·诺依曼效应。当倒锥形水容器撞击…时，遵循冯·诺依曼效应可以很容易地产生高速液体射流更多的是由高速平头活塞驱动。本项目的目的是对高速液体射流的产生进行数值模拟，并在数值结果的基础上构建一个紧凑的装置，作为冯·诺依曼效应的延伸，能够产生高速液体射流。得到的主要结果如下：(1)数值模拟结果表明，射流速度增益超过活塞速度的50%。(2)反锥体形状的顶角约为22度，所产生的射流速度为3-6公里/S。(3)制作了直径为15 mm的单级气体太阳，驱动初速为0.6-1.5公里/S的弹丸，其无烟粉量为0.5-1.5gr。(4)成功地进行了全息干涉观测，以可视化液体的形成和破碎(5)澄清了液滴的飞行和破碎，结果表明，获得超过6公里/S的高速水射流在技术上是可能的。

High speed liquid jets have been intensively applied to the process of fuel sprays in diesel engines and also water jet cutting technology. However, their peak speed ranges up to 1 km/s. Today neither the method of generating high speed liquid jets nor its underatanding have not yet been technically well developed. Previously the chief investigator of this project has developed atechnology in which by using a single stage gas gun the impact of a flat headed high speed projectile of 1-2 km/s on a liquid container created high speed jets of 3-4 km/s. However, this method required a very elaborately designed non-reusable type nozzle so that it can never be practical. It is well known that in pyro-engineering a reverse cone shaped charge, once detonated, produced a very high speed debris jet along its axis, whose principle is called the von Neumann effect. High speed liquid jets can be readily produced by following the von Neumann effect when a reverse cone shaped water container was impin … More ged by a high speed flat headed piston. This project aims to simulate numerically the generation high speed liquid jets and based upon the numerical result to construct a compact facility which can generate high speed liquid jets as an extension of the von Neumann effect. Results obtained are summarized as following :(1) Numerical simulation revealed that the gain in jet speeds was over 50 % of piston speeds.(2) The apex angle of reverse cone shapes was approximately 22 degree and the resulting jet speed ranged from 3 to 6 km/s.(3) A single stage gas sun of 15 mm bore was manufactured which drove projectiles with muzzle speed of 0.6 to 1.5km/s for the amount of smokeless powder of 0.5 to 1.5 gr.(4) Holographic interferometric observations have been successfully carried out to visualize the formation and fragmentation of liquid jets.(5) The flight and fragmentation of liquid droplets have been clarified and their results revealed that it is technically possible to obtain a high speed water jet exceeding over 6 km/s. Less