Transition of Combustion Mode in Scramjet

超燃冲压发动机燃烧模式的转变

• 批准号: 13450394
• 负责人: MASUYA Goro
• 金额: $ 6.53万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13450394/
• 关键词: Scramjet; Dual Mode Combustion; Pseudo-Shock Waves; Mixing

Scramjet engines keep high performance in a wide Mach number range by shifling the combustion from the subsonic mode to the supersonic mode. This mode transition is a complicated interaction among mixing, combustion and pseudo-shock wave, and its detailed mechanism has not been clarified. This research project intends to clarify the transition mechanism by separating each phenomenon in the interaction and by controlling each phenomenon independently to investigate its influence to others.As the first step of the research, helium was injected into a supersonic flow produced by a suction-type wind tunnel. The pseudo-shock wave was produced and controlled by a back-pressure valve installed at the exit of the test section. The pseudo-shock wave strongly enhanced mixing of helium. The more upstream the pseudo-shock wave went, the stronger the enhancement effect became, The helium jet injected from the bottom wall of the test section usually spread in the lateral direction by the pseudo-shoc … More k wave, but the helium was diffused in the transverse direction depending on the location of the front of the pseudo-shock wave.In the second step, the back-pressure valve was removed and a plasma torch was attached as an injector. The feedstock of the torch was nitrogen or hydrogen/nitrogen mixture. The pseudo-shock wave was produced by increasing the input power to the torch and/or the fraction of hydrogen in the feedstock. It was found that the pseudo-shock wave was established when the generalized choking condition was satisfied at the exit section.When the front of the pseudo-shock wave went upstream about four times of the duct height from the injection port, the streamwise wall pressure distribution had a peak near the injection prot and decreased in the downstream direction. The shock train in the pseudo-shock wave was seen only upstream of the injection port fuel was injected upstream the plasma torch. These result indicated that the combustion mode shifted from supersonic to subsonic. The amount of heat release measured at the exit section was less than the value required for the thermal choking in the quasi-one-dimensional theory. The transition of the combustion mode resulted increase of the penetration of the injectant, but no significant change was observed in the hydrogen distribution and the combustiorn efficiency. Less

超燃冲压发动机通过将燃烧从亚音速模式转换到超音速模式，在较宽的马赫数范围内保持高性能。这种模式转变是混合、燃烧和伪激波之间的复杂相互作用，其详细机制尚未阐明。本研究项目将相互作用中的各种现象分离出来，通过独立控制各种现象来研究其相互影响，从而弄清转捩的机理。作为研究的第一步，在由吸气式风洞产生的超音速气流中注入氦气。伪冲击波的产生和控制由安装在试验段出口处的背压阀。伪激波强烈地增强了氦的混合。伪激波越向上游，增强效应越强，从试验段底壁注入的氦气射流通常在伪激波的作用下沿横向扩散， ...更多信息 第二步，去掉背压阀，装上等离子体炬作为喷射器。火炬的原料是氮气或氢气/氮气混合物。伪冲击波是通过增加火炬的输入功率和/或原料中氢的分数来产生的。结果表明，当出口截面满足广义扼流条件时，伪激波形成，伪激波的前沿向上游移动到距喷孔约4倍高度处时，流向壁面压力分布在喷孔附近有一峰值，沿下游方向逐渐减小。伪激波中的激波串仅在喷射口的上游被看到，燃料在等离子体炬的上游被喷射。这些结果表明，燃烧模式从超音速向亚音速转变。在出口段测得的热释放量小于准一维理论中热阻塞所需的值。燃烧模式的转变使喷注剂的穿透深度增加，但氢的分布和燃烧效率没有明显变化。少

项目成果

G. Masuya, et al.: "Mixing and Combustion of Fuel Jet in Pseudo-Shock Waves"Journal of Propulsion and Power, submitted.

G. Masuya 等人：“伪冲击波中燃料喷射的混合和燃烧”，推进与动力杂志，已提交。

S. Ogawa, et al.: "Fuel Mixing Enhancement by Pre-Combustion Shock Wave"Journal of Propulsion and Power, submitted.

S. Okawa 等人：“通过预燃烧冲击波增强燃料混合”，提交于《推进与动力杂志》。

S.Ogawa, et al.: "Fuel Mixing Enhancement by Pre-Combustion Shock Wave"Journal of Propulsion and Power. (投稿中).

S. Okawa 等人：“通过预燃烧冲击波增强燃料混合”《推进与动力杂志》（进行中）。

G.Masuya, et al.: "Mixing and Combustion of Fuel Jet in Pseudo-Shock Waves"Journal of Propulsion and Power. (投稿中).

G.Masuya 等人：“伪冲击波中燃料喷射的混合和燃烧”推进与动力杂志（进行中）。