Study on Stabilization of Supersonic Combustion Using Ram Accelerator

冲压式加速器超音速燃烧稳定性研究

• 批准号: 12450394
• 负责人: TAKI Shiro
• 金额: $ 9.47万
• 依托单位: HIROSHIMA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12450394/
• 关键词: Ram Accelerator; Supersonic Combustion; Shock Waves; Detonation; 超音速年少

The main objects of the present research are to find the properties on the stability of the flame holding in supersonic flows of the combustible gas mixtures, as well as to show that the ram accelerator works as a powerful device to study the supersonic combustion. The ram accelerator we have developed in Hiroshima University is designed as a tool to make fundamental studies on the interactions of combustion with the shock waves, the boundary layer, and so on, so that tube has a rectangular cross section where parallel glass windows are mounted for optical observations. Then, we have got pictures of the flames in the supersonic flows, and the burning flow fields are made clear for various conditions. Flame holding properties are investigated for the different wedge angles and shapes of the side bodies of the projectile, or for the effects of boundary layer thickness. It is also shown that the back-step of the projectile is the most important part as a flame holder. A shock wave is always formed in front of the leading flame, which means the flame exists only in the subsonic region. The flow fields are so complicated that the numerical simulations are necessary to study the supersonic combustion. The computer program is also developed including full kinetic reactions of the CH_4-O_2-CO_2 mixtures, comparable to the experimental observations. Because of the practical necessary, CH_4-O_2-N_2 mixture system is to be used in experiments and the numerical simulations. The ram accelerator is working with the sub-detonative speed of the projectile, though super-detonative mode is also important. The properties of the detonations are also recently studied as a new propulsive device as a pulse detonation engine.

本研究的主要目的是发现可燃气体混合物在超声速流动中火焰稳定性的特性，以及表明冲压加速器作为研究超声速燃烧的有力装置。我们在广岛大学开发的冲压加速器被设计成一种工具，用于对燃烧与激波、边界层等的相互作用进行基础研究，因此管具有矩形横截面，其中安装有平行的玻璃窗，用于光学观察。然后，我们得到了超音速流中的火焰图像，并清楚地显示了各种条件下的燃烧流场。研究了不同楔角、不同侧体形状以及边界层厚度对火焰稳定性的影响。研究还表明，后台阶是弹丸最重要的火焰保持器。激波总是形成在领先火焰的前面，这意味着火焰只存在于亚音速区域。超声速燃烧的流场是如此复杂，数值模拟是研究超声速燃烧的必要手段。本文还编制了包括CH_4-O_2-CO_2混合物全动力学反应的计算机程序，与实验观测值相当。由于实际的需要，本文采用CH_4-O_2-N_2混合物体系进行实验和数值模拟。冲压加速器以弹丸的亚爆速工作，但超爆速模式也很重要。作为一种新型的推进装置，脉冲爆震发动机的爆震特性也是近年来研究的热点。