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Methane hydrogen hybrid turbulent combustion phenomena in a high temperature low oxidizer

高温低氧化剂中甲烷氢混合湍流燃烧现象

基本信息

批准号：
16560193
负责人：
YAHAGI Yuji
金额：
$ 2.37万
依托单位：
Shibaura Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16560193/
关键词：
diffusion combsution lean combustion oxidizer preheatin low oxidizer bi-fuel NOx CO_2 turbulent combustion NO_x CO_2 NO_2

项目摘要

The effect of oxidizer preheating and dilution levels of fuel and oxygen on the combustion phenomena were investigated experimentally and numerically on an opposite turbulent flow fields. The oxidizer preheating and dilution levels are characterized by the magnitude of stoichometric mixture fraction (Fst). As overall feature of the extinction limits, the flame can be maintained to increase in the fuel concentration of opposite side, even when one side fuel concentration is reduced. Obviously, the turbulence conditions affect significantly on the extinction limits. The extinction limit is not influenced on the turbulence added in the LPF side. However, in the case of the turbulence added in the LDF side, the extinction limits is increased. In the regime of F_<st><0.5, the extinction limits of the laminar flame and turbulent flame are significantly dividing from the laminar flames.Near the extinction condition, the local quenching phenomena can be observed. If the large area of the local quenching occurs in the stagnating point, the local quenching area developed to the global extinction. However, the local quenching is not always trigger to develop the global extinction. Most of cases, the flame can recover from the local quenching phenomena. There are two distinct the local quenching recovery mechanism. One is the local quenching, which occurs at the stagnation point. In this case, the LPF propagates into the local quenching area. Then the flame can be recovered from the local quenching phenomena. The other local quenching occurs at the outside form the stagnating point. In this case, the local quenching area is drifted with the diverging flow from the stagnating point. The flame can be automatically recovered in accordance with the opposite flow properties.

在相反的湍流流场中，通过实验和数值模拟研究了氧化剂预热、燃料和氧气稀释度对燃烧现象的影响。氧化剂的预热和稀释程度由化学均质混合分数(Fst)的大小来表征。作为熄火极限的总体特征，火焰在对侧燃料浓度增大的情况下，即使一侧燃料浓度降低，火焰也能维持。显然，湍流条件对消光极限有很大影响。消光极限不受添加在LPF侧的湍流的影响。然而，在LDF侧加入湍流的情况下，消光极限增加。在F_&lt；st&gt；&lt；0.5区域，层流火焰和湍流火焰的熄灭极限与层流火焰明显不同，在接近熄灭条件时，可以观察到局部熄灭现象。如果在停滞点出现大面积的局部淬火，则局部淬火区域发展到整体灭绝。然而，局部猝灭并不总是触发全球灭绝的原因。大多数情况下，火焰可以从局部熄灭现象中恢复过来。存在两种截然不同的局部淬火回复机制。一种是局部淬火，它发生在停滞点。在这种情况下，LPF传播到局部猝灭区。然后，火焰可以从局部熄灭现象中恢复出来。另一种局部淬火发生在停滞点的外侧。在这种情况下，局部淬火区域随着发散流从停滞点漂移。火焰可以根据相反的流动特性自动恢复。