Development of High Turbulence BGR Ultra-low NOx Combustor for Liquid Fueled Micro Gas turbine

微型燃气涡轮机系统在国内某能源厂的应用受到了广泛的关注。从燃料的观点来看，即使在地震等紧急情况下，由于燃料供应的安全性和平稳性，使用液体燃料的能源工厂是理想的。此外，发电厂的燃烧排放应最大限度地减少，以供日常使用。为此，研制了一种以液体煤油为燃料的超低NOx燃烧室，作为微型燃气涡轮机燃烧室。所研制的燃烧室具有独特的流动系统，称为向上旋流。这种流动可以形成向上的回流和燃烧气体的再循环，是有效的火焰稳定与高湍流。此外，它是有效的，以实现低氮氧化物燃烧的效果BGR。主要结果如下。(1)主燃区长度过长会导致CO、NOx等有害燃烧增加，火焰稳定性降低。(2)涡流发生器的叶片角度对发动机性能影响不大，但取消涡流发生器后HC和CO排放增加。(3)在主燃区底端设置导风叶片对火焰稳定有很强的作用。为了稳定火焰，需要足够的叶片高度。为了稳定火焰，主燃区出口处的喉道直径也需要足够大。(4)通过对主燃区、旋流器、导风叶片和出口喉道尺寸的优化设计，使燃烧室具有足够的排放性能。在一次过量空气系数为1.5 〜 1.6的情况下，可以实现Nox排放指数小于0.8 g/（kg-fuel）、CO排放指数小于10 g/（kg-fuel）

Micro gas turbine system is now received much attention for a local energy plant. As for the viewpoint of fuel, an energy plant using liquid fuel is desirable because of safety and smooth fuel supply even id the emergency situation such as earthquake. Also combustion emission from energy plant should be minimized for daily use of the plant. Ultra low Nox combustor with liquid kerosene fuel is developed as a micro gas turbine combustor for this purpose. The developed combustor has a unique flow system that is called upward swirl flow. This flow can form the upward reverse flow with burned gas re-circulation and is effective for flame stabilization with high turbulence. Also it is effective to attain a low Nox combustion by the effect of BGR. The main results obtained here are as follows. (1) Longer length of primary combustion zone results the undesirable combustion such as CO and Nox increases and low stability of flame. (2) The effect of vane angle of the swirl generator is not so much, however HC and CO emissions increase when the swirl generator is eliminated. (3) Air guide vane set at the bottom end of primary combustion zone shows the strong effect on the flame stabilization. For flame stabilization, enough height of vane is needed. Also an enough size of throat diameter at the outlet of primary combustion zone is needed for flame stabilization. (4) An optimization among the size of primary combustion zone, swirl generator, air guide vane and outlet throat results the enough emission performance of the combustor. Nox emission index less than 0.8 g/ (kg-fuel) and CO emission index less than 10 g/ (kg-fuel) can be attained under the primary excess air ratio of 1.5 〜 1.6