Fundamental Study on Scram Jet Engines

超燃喷气发动机基础研究

• 批准号: 02302037
• 负责人: KAJI Shojiro
• 金额: $ 13.95万
• 依托单位: University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Co-operative Research (A)
• 财政年份: 1990
• 资助国家: 日本
• 起止时间: 1990 至 1991
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02302037/
• 关键词: Aerospace propulsion; SCRAM jet engine; Supersonic air intake; Turbulent diffusion; Supersonic combustion; Heat pipe; Ceramics

In order to realize the SCRAM jet engine which is the most promising propulsion system for space planes and hypersonic transports, this research project aims at fundamental study in the four important fields :(1) Air intake, (2) Fuel injection and mixing, (3) Supersonic combustion, and (4) Thermal protection structure and materials.(1) In the air intake research the focus was put on the stable operation of inlets, and compound choking phenomena due to sucking of airframe boundary layer flows into engine and transient unstart and restart phenomena were investigated. Results show that the airframe boundary layer flow easily leads engines unstart, but that the swept side cowl inlet easily recovers from unstart to restart.(2) The study on fuel injection and mixing progressed understandings on flow mechanics and turbulent mixing process of fuels injected into a supersonic stream. Two-dimensional as well as three-dimensioanl injection experiments were conducted, and the correlation between mixing efficiency and total pressure loss were clarified. Numerical simulation technique for a two-dimensional injection model was established.(3) The purpose of supersonic combustion is first to realize combustion of hydrogen in the supersonic stream, and secondly to study importance of factors which control supersonic combustion processes. In the experiments parallel-to-flow injection as well as normal-to-flow injection were adopted, and the effect of combustion on flow mechanics were made clear via optical observation on the structure of shock waves and flames.(4) In the field of thermal protection structure and materials, a high performance cooling structure was constructed applying the heat pipe concept to a two-dimensional panel, and its basic characteristics were studied. In the research for high temperature materials, the fracture mechanics of ceramics were investigated especially on the relation between the strength of grain boundaries and temperature.

为了实现最有希望成为空天飞机和高超声速运输机推进系统的SCRAM喷气发动机，本课题主要开展了以下四个方面的基础研究：（1）进气道;（2）燃料喷射与混合;（3）超声速燃烧;（4）热防护结构与材料。(1)在进气道研究中，重点研究了进气道的稳定工作，研究了机体边界层气流吸入发动机引起的复合阻塞现象以及瞬态不起动和再起动现象。结果表明，机体边界层流动容易导致发动机不起动，而后掠进气道则容易从不起动恢复到再起动。(2)对燃料喷射与混合的研究，加深了对燃料喷射到超音速流中的流动机理和湍流混合过程的认识。进行了二维和三维喷注实验，阐明了混合效率与总压损失之间的关系。建立了二维注射模型的数值模拟技术。(3)超声速燃烧的目的首先是实现氢气在超声速气流中的燃烧，其次是研究控制超声速燃烧过程的因素的重要性。实验中采用了平行流和垂直流两种喷射方式，通过对激波和火焰结构的光学观察，明确了燃烧对流动力学的影响。(4)在热防护结构与材料领域，将热管概念应用于二维平板，构建了一种高性能冷却结构，并对其基本特性进行了研究。在高温材料的研究中，对陶瓷材料的断裂力学进行了研究，重点研究了晶界强度与温度的关系。