Numerical simulation of heat flow field and NOx concentration field in gas combustor
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摘要:
对于一种燃气燃烧器，选取合适的燃烧室尺寸进行匹配，进而构成一个完整的计算区域. 天然气燃料和助燃空气通过该燃气燃烧器喷入燃烧室实现完整燃烧过程. 通过简化燃气燃烧器完成几何建模，使用热流与燃烧分析软件对计算区域进行数值模拟，选用Realizable k-ε湍流模型、ED燃烧模型、DO辐射模型及热力型NOx生成模型，探究过量空气系数α对该燃气燃烧器燃烧过程的影响，得出其温度场及生成NOx浓度场的相关云图及分布情况并进行分析. 当过量空气系数α = 1.1时，NOx浓度最大. 研究结果可为相关研究实验和设计低NOx燃烧器提供参考依据.
Abstract:For a kind of gas burner, the appropriate size of the combustion chamber is selected to match, and then a complete calculation area was formed. Natural gas fuel and combustion air were injected into the combustion chamber through the gas burner to realize the complete combustion process. By simplifying the gas burner to complete geometric modeling, heat flow and combustion analysis software were used for numerical simulation of the calculation area, and the Realizable k-ε turbulence model, ED combustion model, DO radiation model and thermal NOx generation model were selected to explore the influence of excess air coefficient α on the combustion process of the gas burner. The cloud image and distribution of temperature field and NOx concentration field were obtained and analyzed. When the excess air coefficient α = 1.1, the NOx concentration reached the maximum. The research results can provide reference for relevant research experiments and design of low NOx burners.
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Key words:
- gas burner /
- nitrogen oxide /
- numerical simulation /
- excess air coefficient
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图 3 4种不同网格数量的温度分布及速度分布曲线
Figure 3. Four kinds of temperature distribution and velocitydistribution curves with different grid numbers
图 5 不同过量空气系数下计算域中心截面的轴向温度云图（Y = 1 m）
Figure 5. Axial temperature nephogram of central section of calculation domain under different excess air coefficients (Y = 1 m)
图 6 不同过量空气系数下计算域中心截面的径向温度云图（Z = 1 m）
Figure 6. Radial temperature nephogram of central section of calculation domain under different excess air coefficients (Z = 1 m)
图 7 不同过量空气系数下计算域中心截面的氮氧化物分布云图
Figure 7. Clouds of nitrogen oxide distribution in the central section of calculation domain under different excess air coefficients
图 8 不同过量空气系数下燃烧室出口的NOx浓度分布曲线
Figure 8. Distribution curve of NOx concentration at outlet of combustion chamber under different excess air coefficients
表 1 燃烧室模型相关尺寸
Table 1. Combustion chamber model related dimensions
半径/m 长度/m 半径长度比 出口半径/m 出口角度/（°） 0.4 1.8 0.222 0.175 50 
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表 2 采用的求解模型
Table 2. Adoption of solving model
求解模型 采用形式 湍流模型 Realizable k-ε模型 燃烧模型 涡耗散ED模型 辐射模型 DO辐射模型 NOx形成模型 热力型NOx模型
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表 4 4种网格数量与网格节点数量
Table 4. Four kinds of grids numbers and grid nodes numbers
网格编号 网格数量 网格节点数量 1 516345 90881 2 1192578 203881 3 1532122 261444 4 2010254 342451
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