【摘要】 运用数值方法对U型燃烧室内天然气高温空气燃烧进行研究,其中湍流流动采用雷诺应力模型,燃烧采用涡团耗散模型,耦合辐射传热模型;NO生成考虑了热力型NO生成机制和快速反应NO生成机制。其数值计算结果与相应实验结果吻合较好。分析了助燃空气温度、过量空气系数、助燃空气中氧浓度对燃烧特性的影响。研究表明:随着助燃空气温度增加,燃烧室气体温度升高,壁面平均热流和出口NO浓度增大;随着过量空气系数的增加,燃烧的最高温度和NO排放增加,气体平均温度及热流密度先增加后减小,过量空气系数为1.2时温度均匀性好,传热量最大;随助燃空气中氧浓度减小燃烧室温度均匀性增强,壁面平均热流增大,NO生成量显著减小。更多还原

【Abstract】 The combustion characteristics of natural gas with high-temperature air combustion technology in a U-type combustion chamber were studied numerically. The eddy dissipation combustion model (EDM) coupled with Speziale, Sarkar and Gatski Reynolds stress model (RSM) was applied to model turbulence combustion. The effect of radiation heat transfer was considered. The thermal and prompt NO formation models were employed to calculate NO emissions. Results of numerical simulation were in line with the corresponding experimental data. The effects of some key parameters such as combustion air temperature, excessive air ratio and oxygen concentration on combustion characteristics were systematic discussed. The gas temperature, average wall heat flux and NO increase with the combustion air temperature increasing. The maximum gas temperature and NO emissions increase with the combustion excessive air ratio increasing, the average gas temperature and heat flux increase at first and then decrease, and the maximum heat flux can be obtained when the excessive air ratio is 1.2. The uniformity of gas and average wall heat flux increase with the oxygen concentration of combustion air decreasing, and NO generation decreases significantly.更多还原