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A Study on Mixing Enhancement of Shear Layer by Streamwise Vortex Formed in a Supersonic Flow.

超音速流中流向涡增强剪切层混合的研究。

基本信息

批准号：
17360407
负责人：
KONO Michikata
金额：
$ 9.54万
依托单位：
University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17360407/
关键词：
Supersonic Flow Shear Laver Streamwise Vortex SCRAM Jet Liquid Fuel Mixing Enhancement 流体力学的不安定スクラムジェットエンジン

项目摘要

Effects of a curved trailing edge on growth of a compressible "single" shear layer are investigated experimentally. The results are directly compared with those for a compressible "double" shear layer. Several types of sine-curved trailing edges are used to induce streamwise vortices into the shear layer. The wavelength of the sine curve is varied widely. It is shown that spanwise vortices due to the primary instability are much more obscure and the spacing varies widely, when compared with those for the compressible double shear layer. And it is shown that, by use of the curved trailing edge, streamwise vortices are induced into the flow. By use of the curved trailing edge, the growth rate of the compressible single shear layer slightly increases. However, when compared with the compressible double shear layer, the increase in the growth rate is much smaller. It is shown that the curved trailing edge is effective for mixing enhancement only when it is used for a compressible double sh … More ear layer.Streamwise vortex structure induced by secondary instability of compressible shear flow was numerically investigated. Parallel shear flow with convective Mach number 0.4 was used in the present study. From linear stability analysis, existence of streamwise vortex structure components was confirmed, and scale ratio which gives maximum amplification rate was specified. In addition, spatially evolving shear flow was investigated by three-dimensional calculation. Streamwise vortex structure similar to that gotten from liner stability analysis was observed. In the case where white-noise-like disturbance was introduced, growth rate of shear layer was estimated and effect of streamwise vortex structure on growth of shear layer was investigated. Due to streamwise vortex structure induced by secondary instability, growth rate in three-dimensional calculation was larger than the case of two-dimensional case.An experimental research on supersonic combustion of kerosene was conducted in a model scramjet combustor with six kinds of cavities. Kerosene was injected into a Mach 2 vitiated air stream perpendicular to the direction of the air flow ahead of a cavity. Kerosene was injected at an atomized state by using nitrogen as barbotage gas or using nitrogen and pilot hydrogen. As a result, it became apparent that not only the size of cavity but also mutual interference of shock waves had much effect on a kerosene auto-ignition. And the cavity size had also a considerable impact on a flame-holding at low temperature conditions. Moreover, the barbotage gas pressure for an effervescent atomization technique had a significant effect on the ignition and the flame-holding of kerosene. Less

实验研究了弯曲后缘对可压缩“单”剪切层生长的影响。结果直接与可压缩“双”剪切层的结果进行了比较。几种类型的正弦弯曲尾缘被用来诱导流向涡进入剪切层。正弦曲线的波长变化很大。结果表明，与可压缩双剪切层相比，由初级失稳引起的展向涡更加模糊，间距变化也很大。结果表明，利用弯曲的尾缘，可以诱导向流涡进入流动。采用弯曲尾缘后，可压缩单剪切层的生长速率略有提高。但与可压缩双剪切层相比，其生长速率的增幅要小得多。结果表明，弯曲尾缘仅用于可压缩双侧耳层时，对混合增强有效。对可压缩剪切流二次失稳诱导的流向涡结构进行了数值研究。本文采用对流马赫数为0.4的平行剪切流。通过线性稳定性分析，确定了流向涡结构分量的存在性，并确定了放大率最大的尺度比。此外，通过三维计算对剪切流的空间演化进行了研究。观察到与线性稳定性分析结果相似的流向涡结构。在引入类白噪声扰动的情况下，估计了剪切层的生长速率，并研究了顺流涡结构对剪切层生长的影响。由于二次失稳引起的流向涡结构，三维计算的增长速率大于二维计算。在具有6种空腔的超燃冲压发动机模型燃烧室中进行了煤油超声速燃烧实验研究。煤油被注入与空腔前方气流方向垂直的2马赫污浊气流中。以氮气作为瓦斯或以氮气和先导氢气为燃料，在雾化状态下注入煤油。结果表明，不仅空腔的大小对煤油自燃有很大影响，而且激波的相互干扰对煤油自燃也有很大影响。在低温条件下，空腔尺寸对火焰的保持也有相当大的影响。此外，泡腾雾化技术的瓦斯压力对煤油的点火和保燃性有显著影响。少