Mixing Control System Using Micro Nozzle of 3D Vortex Generator and Flame holder Aiming at High-Speed Diffusion Combustion

利用3D涡流发生器和火焰保持器的微喷嘴实现高速扩散燃烧的混合控制系统

• 批准号: 12450087
• 负责人: YOSHIDA Hideo
• 金额: $ 9.66万
• 依托单位: KYOTO 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-12450087/
• 关键词: combustion; high-speed diffusion combustion; flame holding; micro nozzle; mixing control

For combustors of microturbines, enhancement of flame holding and mixing in a high-speed flow is crucial to make the combustor compact and also realize isothermal expansion combustion. To this end, we propose a combined nozzle and flame holder with small dimensions. That is, in the downstream of relatively high-temperature gas flow, a micro object, the shape of which is similar to an angel fish, is introduced as a fuel injector: on the back side of the injector, intense turbulence is generated.In the experiment, first, we prepared a high-speed and high-temperature wind tunnel. The attained maximum velocity and temperature were 105m/s and 550℃, respectively. Secondly, V-type and U-type fuel injectors which are two or three times larger than the final ones were used to obtain fundamental mixing and flame holding characteristics; their length and width are 1.5mm and 1mm, respectively. The V-shaped injector shows higher flame holding performance than the U-shaped injector, which indicates the validity of an angel-fish type micro injector.On the other hand, to clarify the mixing mechanism on the back side of the micro injector in detail, a numerical calculation using k-e turbulence model was conducted varying the injector geometry, As a first step of the numerical analysis, a flow around backward facing step with concave wall was analyzed. It was found that for the case with the concave wall the streamwise length of a recirculation zone decreases. The velocity near the concave wall, where fuel-injection holes are installed, was about 1% of that of the main flow. These facts are preferable in terms of the mixing enhancement.From the experimental and theoretical studies during 2000-2002, we conclude that the high potential of the present micro fuel injector as a high-speed diffusion combustion has been confirmed. An actual application to a microturbine combustor is now in progress.

对于微型涡轮机燃烧室来说，增强高速流动中的火焰保持和混合对于使燃烧室紧凑并实现等温膨胀燃烧至关重要。为此，我们提出了一种小尺寸的组合式喷嘴和火焰保持器。即在相对高温气流的下游，引入一个形状类似天使鱼的微小物体作为喷油器：在喷油器的背面，产生强烈的湍流。在实验中，我们首先准备了一个高速高温的风洞。达到的最大速度和温度分别为105m/s和550℃。其次，采用比最终产品大两到三倍的V型和U型喷油器，以获得基本的混合和火焰稳定特性；它们的长度和宽度分别为1.5mm和1mm。 V 形喷射器表现出比 U 形喷射器更高的火焰稳定性能，这表明了天使鱼型微型喷射器的有效性。另一方面，为了详细阐明微型喷射器背面的混合机制，使用 k-e 湍流模型进行了不同喷射器几何形状的数值计算。作为数值分析的第一步，凹壁后向台阶周围的流动 被分析了。发现对于具有凹壁的情况，​​再循环区的流向长度减小。设有喷油孔的凹壁附近的流速约为主流流速的1%。这些事实对于增强混合来说是有利的。从2000-2002年期间的实验和理论研究来看，我们得出的结论是，目前的微型燃料喷射器作为高速扩散燃烧的巨大潜力已经得到证实。目前正在对微型涡轮燃烧器进行实际应用。