Development of a small-sized apparatus for hypervelocity impact experiment in a standard-scale laboratory of one unit

二级轻气炮是目前唯一一种能使小型弹丸加速超过3 km/s、重复性好的发射装置。该发射装置需要安装在与其他设施隔离的大型实验室中，因为它的安全操作和对环境的安静。然而，一个非常小尺寸的二级轻气炮，即所谓的微型炮，可以设计成一个午餐器，安装在地面面积为30平方米的标准规模实验室中。该炮的发射管和压缩管的内径分别为1.58 mm和9 mm，发射管和压缩管的内径分别为1.58 mm和9 mm，发射管和压缩管的内径分别为1.58 mm和9 mm，这种选择的原因之一是市场上的高压管可以用作这些管。飞片法是一种简单而精确的弹丸速度测量方法，该方法需要制备铁磁材料弹丸，质量密度为5.1 g/cm 2的MnAl合金球形射弹3、直径为1 mm，每枚弹丸装在尼龙弹托内作为飞片，在发射管内对部分弹丸进行了加速试验，并对试验结果进行了分析参数如下;试验结果表明，该微型二级轻气炮在安全氦气的作用下，弹丸加速速度可达5 km/s，研制成功。

Atwo-stage light gas gun is the only launcher which can accelerate a small projectile over 3 km/s with good reproducibility. This launcher needs to be set up in a large-scale laboratory isolated from other facilities because of its safety operation and silence for environment. However a very small-sized two-stage light gas gun, so called a micro gun, could be designed as a luncher to be set up in a standard-scale laboratory of 30 m^2 in floor surface. It was successfully constructed on a base of only 2.8 min length.This gun was designed to be modified easily in sizes of its launch tube and compression tube which act effectively on projectile acceleration.The launch tube and compression one have the inner diameters of 1.58 mm and 9 mm, respectively for standard operation.One of reasons for this selection is that high-pressure tubes on the market can be used as these tubes.A magne'to-flyer method was adopted for simple and precise measurement of projectile velocity.A projectile made of ferromagnetic material needs to be prepared for this method.Thus, sphere-shaped projectiles of MnAl alloy with mass density of 5.1 g/cm^3 and diameter of 1mm were made.Each projectile was put in a sabot made of nylon as a flyer in the launch tube.Acceleration experiments were conducted with respect to some of the parameters as follows ; amount of charge, thickness of a diaphragm set between the launch tube and a high-pressure coupling, weight of a piston for light-gas compression, and weight of a projectile.Experimental results showed that this micro two-stage light gas gun can accelerate a projectile up to 5 km/s by using of safety helium gas, and that this gun was successfully developed.