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Study on effects of chemical reaction rates on ram accelerator thrust performance

化学反应速率对冲压加速器推力性能影响的研究

基本信息

批准号：
07651118
负责人：
SASOH Akihiro
金额：
$ 1.6万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07651118/
关键词：
Ram accelerators Shock waves Chemical reaction Detonation

项目摘要

Numerical analyzes and ram accelerator operation experiments were conducted with the aim of clarifying relationships between its thrust performance and chemical reaction rates. There exist two propulsive modes in which subsonic combustion occurs ; subdetonative and transdetonative modes. In this study, numerical analyzes were based on quasi-one-dimensional steady flow with finite-rate chemistry taken into account. The formulation yields ordinal differential equations solution of which can be obtained through a well-developed implicit method. Instability in the calculation due to sonic singularity was avoided by a method which was developed uniquely in this study. The analyzes shows a propulsive mode is determined by the relationship between a characteristic length of finite-rate chemical reactions and a projectile length ; in a large apparatus the transdetonative propulsive mode tends to appear at relatively low Mach numbers. This result suggests that a small apparatus has an advantage to obtain stable subdetonative mode. For a large apparatus, a similar operation is possible by adjusting the fill pressure of the mixture. The experiments were conducted using a world-smallest working ram accelerator with a 25-mm-bore. As was predicted by the analyzes, ram acceleration was realized with a relatively energetic mixture. This study points out the importance of a chemical reaction induction length in determining the thrust performance. This conclusion should lead to further development of quantitative clarification of the scaling laws on ram accelerators.

为了弄清推力性能与化学反应速率之间的关系，进行了数值分析和冲压加速器运行实验。亚音速燃烧有两种推进模式：亚爆轰和跨爆轰。在本研究中，数值分析基于考虑了有限速率化学的准一维定常流动。该公式产生了有序的微分方程组，其解可以通过发展成熟的隐式方法来获得。本文提出的一种方法避免了由于声速奇异性引起的计算不稳定问题。分析表明，推进模式由有限速率化学反应的特征长度和弹丸长度之间的关系决定；在大型装置中，跨爆轰推进模式往往出现在相对较低的马赫数。这一结果表明，小型装置在获得稳定的亚爆轰模式方面具有优势。对于大型仪器，通过调整混合物的填充压力也可以进行类似的操作。这些实验是使用世界上最小的25毫米口径的工作冲压加速器进行的。正如分析所预测的那样，冲压加速是用一种相对高能的混合物实现的。本研究指出化学反应诱导长度在决定推力性能中的重要性。这一结论应有助于进一步定量阐明冲压加速器的定标规律。