煤粉炉内扩散火焰关于大尺度涡的“砂轮”效应初探

以110MW、四角切向喷射的煤粉动力锅炉为对象，借助CFX4.2软件，在α-250工作站对该型锅炉的燃烧过程开展了数据模拟研究，研究发现：在该型炉膛内存在某种由准强制涡和准自由涡所组成的涡结果，这些涡均属于大尺度涡（非亚格子涡）；在这些准强制涡和准自由涡即大尺度涡之间以及某些涡与固壁或涡与喷射气流之间因扩散燃烧及强剪切而导致局部火焰增强现象即所谓“砂轮”效应，从Zeldovich转换和广义Reynolds比拟及粘性耗散的角度，定性地分析了这一效应。

Discussion on Grinding Wheel Effect of Diffusion Flame to Large Scale Eddy in Pulverized Coal Boiler

This paper takes pulverized coal boiler with jets of tangent direction of four corner on furnace wall as an object,and studies the combustion process of the pulverized coal boiler with CFX4.2 software by α-250 workstation.Researches find that there are some regular eddy-structure of approximate solid (rigid) eddy (vortex) and approximate free eddy (both of them are first eddy) and some second eddy on normal and cross sections(those are large scale eddy).This paper also points out that there are strong flame or local strong flame on friction location between one eddy and others,or eddy and wall of furnace,or eddy and jet of air.And this phenomenon is called as frinding wheel effect of the eddy.The phenomenon is analysed by the Zeldovich transformation,the generalized Reynolds analogy and the viscosity dissipation.