DESIGN AND TRIAL MANUFACTURING OF RAM-ACCELERATOR

本研究建立了一套用于研究冲压加速器工作机理的试验性实验装置。该装置由快开阀式驱动管、带自由活塞的压缩管、带卸油箱的发射管和加速管组成。这些管子是制造和组装的。在冲压加速器中，弹丸是通过在车身后面的激波燃烧产生的高压来加速的。为了保持最大推力，爆炸必须产生并稳定在弹体周围的适当位置。因此，这类系统的成功研制取决于对弹丸上的爆轰结构的了解。在这项研究中，冲压加速器中以超音速喷射到加速管中的弹丸周围的反应流是数值…的。更多的模拟，通过使用详细的化学反应模型研究加速过程。在阐述这个问题时，我们做了以下假设。首先，流场是二维轴对称的。其次，气流是无粘性和不导热的，气体在热方面是完美的。因此，所有化学物种的比热都随温度而变化。气体混合物的化学反应速率服从阿累尼乌斯定律。弹丸加速通过的混合物由H2、O2、N2.9种物质(H2、O2、H2O、O、H、OH、HO2、H2O2和N2)和19个反应组成。在这些假设下，控制方程被表示为一般坐标下的欧拉方程。计算机程序采用半隐式预测-校正TVD格式来求解刚性化学反应。RAMAC III基准试验采用弹丸外形，长度80 mm，最大半径7.6 mm。管子半径为10毫米，与崎玉大学的RAMAC设施相对应。计算区域为100 mm×10 mm，包括弹丸周围的网格331_x41，弹丸后面的网格为71_x81。因此，这个计算机代码是可用的，并详细地捕捉到了爆炸结构。对于加速管的每个压力，弹丸获得恒定的加速度。较少

In this research, a trial experimental apparatus for studying the working mechanism of the ram accelerator has been build. The apparatus is consists of a quick open valve type driver tube, a compression tube with a free piston, a launch tube with a dump tank and an accelerating tube. These tubes are manufactured and assembled. The test run was performed to demonstrate that the driver with the free psiton can accelerate a projectile to a speed larger than 600 m/s.In a ram accelerator, a projectile, is accelerated by the high pressure generated by shock-induced combustion behind the body. To maintain the maximum thrust, detonations must be generated and stabilized at appropriate locations around projectile body. Therefore, successful development of such systems depends on understanding of the detonation structure on the projectile. In this study, a reactive flow around the projectile in the ram accelerator, which is ejected into the acceleration tube at a supersonic speed, is numerically … More simulated to investigate an acceleration process by using detailed chemical reaction models. In formulating the problem, the following assumptions are made. At first, flow field is two dimensional and axisymmetric. Secondly, the flow is inviscid and non-heat-conducting, and the gas is thermally perfect. Thus, the specific heats for all chemical species vary with temperature. Chemical reaction rates of the gas mixture obeys Arrhenius'laws. The mixture through which the projectile is accelerating consists of H2, O2, N2.9 species (H2, O2, H2O,O,H,OH,HO2, H2O2 and N2) and 19 reactions are considered. Under these assumptions, governing equations are formulated as the Euler equation in general coordinates. Computer code used is semi-implicit predictor-corrector TVD scheme to solve the stiff chemistry. A configuration of the projectile is adopted as the RAMAC III benchmark test with its length 80 mm and its maximum radius 7.6 mm. The tube radius is 10 mm, which corresponds to RAMAC facility in Saitama University. Parameter is an initial velocity and an initial pressure in the tube, which contains a premixed of 2 H2+O2+3.76 N2 at 300K.Calculation region is 100 mm _x10 mm and includes grids 331_x 41 around the projectile, 71_x81 behind it. As a result, this computer code is available and captured the detonation structure in detail. And projectile is obtained constant acceleration for each pressure of acceleration tube. Less