【摘要】 借助计算流体力学软件Fluent,选择合理的数学模型,对一台600 MW超超临界墙式布置切圆燃烧锅炉进行数值模拟,着重研究了墙式切圆锅炉炉内空气动力场,温度场,组分场和不同SOFA(分离燃尽风)风率对墙式切圆燃烧锅炉NOx生成及烟气成分特性的影响。结果表明:炉内切圆形成完整,炉内充满度较好,但切圆形成过大,近壁面温度过高,结渣倾向明显。此结论与实验台上烟雾示踪实验所得结论相符,证明了模拟的可靠性。随着SOFA风率的增加,主燃区氧浓度降低,主燃区NOx生成量减少,在SOFA风率过高条件下,会使燃烧后期NOx生成大大增加,整体NOx排放并不一定低。因此,需要合理优化SOFA风率。更多还原

【Abstract】 With the help of CFD(computational fluid dynamics) software Fluent and by choosing a rational mathematical model,a numerical simulation was performed of a 600 MW ultra-supercritical wall-type-arranged tangentially-fired boiler.The influence of the aerodynamic field,temperature field,component field and different SOFA(separated over-fired air) air ratios on the NOx generation and flue gas constituent characteristics of the boiler in question were mainly studied.The research results show that the in-furnace tangential circle is completely formed with a relatively good filling degree,but the tangential circle being formed is excessively large,the temperature nearing the wall surfaces is unduly high and the slagging tendency is conspicuous.Such a conclusion is in good agreement with that obtained from the fog tracer test performed on a test stand,having proved that the simulation is reliable.With an increase of the SOFA air ratio,the oxygen concentration in the main combustion zone will decrease and NOx produced in the main combustion zone will also diminish.Under the condition of the SOFA air ratio being excessively high,the NOx produced in the later-stage combustion will increase greatly and the NOx emissions will not be necessarily low as a whole.Therefore,it will be necessary to rationally optimize the SOFA air ratio.更多还原