Research and Development of High-Intensity Hydrogen Combustor for Gas Turbine

由于氢燃料在燃烧时不产生具有温室效应的二氧化碳，因此作为下一代燃料很有吸引力。本研究的目的是开发一种以氢气为主要燃料的微型燃气涡轮机燃烧室。火焰拉伸熄灭层流火焰是氢气-空气预混火焰的一个基本特征。因此，我们首先测量了层流氢-空气预混火焰的熄灭特性。结果表明，氢-空气预混火焰对火焰拉伸的容忍度比典型的碳氢燃料高一个或两个数量级。研究了湍流对湍流预混火焰熄灭的影响，发现Kolmogorov微尺度涡在湍流预混火焰熄灭中起着重要作用。氢气-空气预混火焰的燃烧速度非常快， ...更多信息 闪回因此，我们将扩散燃烧应用于微型燃气涡轮机的燃烧室中。结果表明，在化学反应开始前，冲击射流通过强湍流促进了湍流混合，即使燃料和空气分开供给，也能发生预混燃烧。利用冲击射流设计了大调节比无旋流稳定工作的高强度模型燃烧室。通过对该燃烧室的实验研究，发现冲击射流诱导的湍流特性受空燃动量比的控制。在燃料动量较大的情况下，产生了分布的反应区，燃烧强度极高。将冲击射流的概念应用于微型燃气涡轮机模型燃烧室。为了减少热损失和提高燃烧稳定性，在燃烧室中引入了陶瓷内衬。结果，稳定范围扩大。燃烧室中稳定化学物质的浓度是均匀的，并且发现废气中的NOx浓度极低。因此，空气和燃料的撞击射流可以应用于微型燃气涡轮机的燃烧室。少

Since hydrogen fuel, when it is burned, produces no carbon dioxide which has the greenhouse effects, it is attractive as the fuel of the next generation. The objective of the present study is the development of a combustor for a micro gas turbine in which hydrogen is used as a main fuel. The extinction of laminar flame by flame stretch is a fundamental feature of the hydrogen-air premixed flame. Therefore, at first, we measured the extinction characteristics of the laminar hydrogen-air premixed flames. It was made clear that the hydrogen-air premixed flame has one or two order of magnitude higher tolerance to the flame stretch than the typical hydrocarbon fuels. Then the effect of turbulence on the extinction of the turbulent premixed flame was studied and eddies with the Kolmogorov micro scale were found to play an important role in the extinction of the turbulent hydrogen-air premixed flame. The burning velocity of a hydrogen-air premixed flame is extremely fast and it easily causes … More flash back. Therefore, we apply the diffusion combustion in the combustor of a micro gas turbine. It was found that the impinging jets promote significantly the turbulent mixing by strong turbulence before the chemical reaction begins and that the premixed combustion occurs even though fuel and air are supplied separately. Applying the impinging jets, we designed high-intensity model combustor which operates stably within wide turn-down ratios without swirl. By using this combustor, characteristics of turbulence induced by the impinging jets was found to be controlled by the momentum ratio of air to fuel. For the case of large momentum of fuel, the distributed reaction zone was produced and the combustion intensity was extremely high. The concept of the impinging jets was applied to the model combustor of a micro gas turbine. To reduce the heat loss and to increase the combustion stability, a ceramic liner was introduced in the combustor. As a result, the stability range was widened. The concentration of stable chemical species was uniform in the combustion chamber and NOx concentration in the exhausted gas was found to be extremely low. Therefore, the impinging jets of air and fuel can be applied to the combustor of a micro gas turbine. Less