全预混紧凑缝隙式水冷燃气锅炉燃烧特性模拟

Simulation on combustion characteristics of fully premixed water-cooling gas boiler with compact slit structure

为解决传统燃气锅炉污染物排放量高、体积大等问题,研发了一种全预混冷凝式燃气锅炉,采用并排的水冷板翅插合形成燃烧器头部及冷凝换热段,二者之间设为炉膛,锅炉本体采用挤压铝工艺一体化成型,结构紧凑、换热能力强、耐腐蚀、工艺简单、成本低。由于模型对称,对其基础单元的流场、温度场、火焰长度及污染物排放特性进行数值模拟研究,并通过燃烧实验对模拟结果进行验证。结果表明,该燃气锅炉在12~24k W的热负荷范围内流场均匀,易于点火和稳定燃烧。钝体与火孔出口之间的距离为4mm、钝体宽度为1.0mm、过量空气系数为1.2、燃烧室长度为120mm,满负荷24k W燃烧时,锅炉排放的NOx<95mg/m^(3),CO<50mg/m^(3),锅炉本体尺寸仅为229mm×251mm×60mm,实现了燃气锅炉的超紧凑低排放,对全预混水冷燃气锅炉的节能减排及低碳设计、改造具有重要的现实指导意义。

To solve the problems of high pollutant emission and large volume of traditional gas boilers,a fully premixed condensing gas boiler was developed.The boiler adopted side-by-side water-cooling plate fins inserted to form the burner head and the condensing heat exchange section.The furnace was between the burner head and the condensing heat exchange section.The boiler body was produced by extrusion aluminum process,with compact structure,strong heat transfer ability,corrosion resistance,simple process and low cost.Due to the symmetry of the model,the flow field,temperature field,flame length and pollutant emission characteristics of the basic unit were studied by numerical simulation.And the simulation results were verified by the combustion experiment.The results indicate that the boiler has a uniform flow field in the load range of 12—24kW.It is easy to ignite and burn stably.When the distance between the blunt body and the outlet of the fire hole is 4mm,the width of the blunt body is 1.0mm,the excess air coefficient is 1.2 and the combustion chamber length is 120mm,the NO_(x) emissions are less than 95mg/m^(3) and the CO emissions are less than 50mg/m^(3) at the full load of 24kW.The size of the boiler body is only 229mm×251mm×60mm.The boiler achieves ultra-compact and low emissions,which has important practical guiding significance for energy saving,emission reduction and low-carbon design as well as transformation of fully premixed water-cooling gas boiler.