复杂曲面花瓣燃烧器煤粉燃烧数值分析

应用贴体坐标结构化网格对复杂曲面的花瓣燃烧器进行三维(360°)煤粉燃烧的数值模拟。给出花瓣燃烧器的流场、颗粒场、温度场和浓度场,分析花瓣燃烧器的稳燃及低NOx燃烧原理和特性。计算结果表明,在花瓣稳燃器的作用下,煤粉气流进入炉内能立即在瓣后着火燃烧,并在径向回流区中形成稳定的"值班火焰",为整个风粉气流的着火燃烧提供稳定的热量来源。花瓣燃烧器的火焰在炉内呈花瓣状,造成局部缺氧区,有利于降低NOx的排放和低挥发分煤在广泛负荷范围内的稳定着火和完全燃烧。

Numerical Analysis of the Petal Swirl Burner With Complex Geometry Configuration for Pulverized Coal

A three-dimensional (360°) body-fitted coordinate mathematical model to simulate the coal combustion of petal swirl burner(PSB) is firstly set up. Through the simulation, the fields of the gas flow, the coal particle, the gas temperature and the NOx pollutant concentration for PSB are given. The result shows that owing to the design of petal flame stabilizer(PFS), part of the pulverized coal flow leaving the burner rapidly moves into the radial recirculation zones behind the PFS, and is immediately ignited and burnt which forms the flame always on duty behind each petal. The flame pattern of PSB gives a reliable ignition and steady firing condition for the low volatile coal and for the turndown capacities of the boiler meanwhile for lower NOx emission.