VELOCITY PERFORMANCE IN RAMAC 90 MULTISTAGE EXPERIMENTS
VELOCITY PERFORMANCE IN RAMAC 90 MULTISTAGE EXPERIMENTS
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RAMAC 90 多级实验中的速度性能
DOI：
10.2514/6.1998-3447
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
M. Henner
中科院分区：
文献类型：
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作者：
J. Legendre;M. Giraud;M. Henner
在ISL进行了调查的最高速度性能的实验可获得的光膛冲压加速器在热扼流推进模式和甲烷基混合物在初始压力高达5 MPa。因此，两个演示器，30毫米和90毫米口径，分别在航空弹道靶场设施的发射室操作。这两个演示器的设计允许同时使用多达三种不同的可燃气体混合物，无论是在升级的90毫米口径设施- RAMAC 90-，沿着一个24米长（267口径）的冲压部分，或在30毫米口径设施- RAMAC 30-11 -，沿着一个9米长（300口径）的冲压部分。介绍了热阻塞推进模式下气体混合物分级的星间链路研究现状。无论到目前为止在RAMAC 90中进行的气体混合物分级实验（富含燃料的甲烷氧混合物稀释在不同数量的氮气或氦气中），速度限制都依赖于用于弹丸后体的镁合金，即，从鳍的前缘到基部。这种配备镁合金后体的射弹不允许超过2km/s的速度或在不启动之前在冲压段中花费超过1 Oms的时间长度，即，燃烧区超过射弹。因此，设计了一种新的射弹构型，与全镁合金射弹后体相比，该构型既能增强其抗烧蚀/eros离子的能力，又能获得比纯铝合金射弹后体更高的净推力。本发明公开了一种新的ISL公司的RAMAC射弹设计，该射弹设计装配有半可燃后体，该设计是基于使用在其后基座处装配有镁型材的铝后体。这个后部的尺寸是这样设计的，当炮弹从RAMAC枪口射出时，它大部分都被烧毁了。在RAMAC 30-11装置上，首次给出了用这种弹丸进行的2-混合构型的实验结果。在RAMAC 90装置上进行的试验中，用这种射弹获得的净推力值最有希望。
Investigations are carried out at ISL on the highest velocity performance experimentally obtainable in smooth-bore ram-accelerators in the thermally-choked propulsion mode and for methane-based mixtures at an initial pressure up to 5MPa. Therefore, two demonstrators, 30mm and 90-mm-caliber respectively, are operated in the launch room of the Aeroballistic Range Facility. Both demonstrators are designed to allow the simultaneous use of up to three different combustible gaseous mixtures either in the upgraded 90-mm-caliber facility - RAMAC 90-, along a 24-m-long (267 calibers) ram-section, or in the 30-mmcaliber facility - RAMAC 30-11 -, along a 9m-long (300 calibers) ram-section. This paper is aimed at presenting the state of ISL studies concerning the gas mixture staging in the thermally choked propulsion mode. Whatever gas mixture staging experimented so far in the RAMAC 90 (fuel-rich methaneoxygen mixtures diluted in various amounts of either nitrogen or helium), velocity limitation relied on the magnesium alloy used for the projectile afterbody, i.e., from the leading edge of the fins to the base. Such projectiles equipped with magnesium-alloy afterbodies did not allow to overtake the velocity of 2km/s or a time length spent in the ram-section over 1 Oms before unstarting, i.e., combustion zone overtaking the projectile. Accordingly, a new projectile configuration has been designed which would allow both to enhance its resistance to ablation/eros ion compared to that of total magnesium-alloy projectile afterbody and to allow a net thrust higher than that achieved with pure aluminum-alloy projectile afterbody. The new ISL's RAMAC projectile design fitted with semi-combustible afterbody is disclosed, based on the use of an aluminum afterbody fitted with a magnesium section at its rear base. This rear part is dimensioned so that it is mostly burnt-out when the projectile exits the RAMAC muzzle. First experimental results conducted with such projectiles are presented with a 2-mixture configuration in the RAMAC 30-11 facility. Values of net thrust obtained with this type of projectile appeared most promising for experimentations in RAMAC 90 facility.