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以工业炉的高温空气燃烧技术应用为背景,对一个单烧嘴燃烧室内的高温空气燃烧特性进行了数值研究。燃烧室尺寸为800 mm×800 mm×1 400 mm,燃烧器烧嘴由燃气和高温预热空气多股射流组成,其中燃料射流喷口为圆形,直径为10 mm,位于中心。空气射流喷口为5个等面积的圆形,置于燃气射流喷口周围。湍流输运方程采用标准k-ε双方程模型,气相燃烧模型采用β函数的PDF燃烧模型,辐射换热过程采用离散坐标法模拟,NOx模型为热力型NOx。对燃气射流和空气射流的进口参数对燃烧室内的燃烧特性的影响进行了模拟计算和分析。计算结果表明射流进口参数将影响和改变燃烧室内的烟气回流及其与燃料、空气的混合过程,从而影响局部温度、氧浓度的分布和决定燃烧状况、影响最终的NOx排放量。其中随着燃料射流和空气射流速度比和燃料射流倾角的增大,燃烧室内的烟气回流区域扩大,强化了燃料、空气和烟气的混合,使低氧区域扩大,燃烧室内最高温度和平均温度都降低,NOx生成量明显降低。研究结果对于工业炉的烧嘴设计有一定参考意义。
Based on the application of high temperature air combustion technology in industrial furnace, the combustion characteristics of high temperature air in a single burner are numerically studied. The size of the combustion chamber is 800 mm × 800 mm × 1 400 mm. The burner burner consists of multiple gas jets of hot gas and high temperature preheated air. The fuel jets are circular with a diameter of 10 mm and are located in the center. Air jet spout for the 5 equal area circular, placed around the gas jet spout. The turbulent transport equation uses the standard k-ε two-equation model, the gas-fired combustion model uses the beta function PDF combustion model, the radiation heat transfer process is simulated by the discrete coordinate method, and the NOx model is the thermal NOx. The influence of the inlet parameters of gas jet and air jet on the combustion characteristics in the combustion chamber was simulated and analyzed. The calculation results show that the jet inlet parameters will affect and change the flue gas backflow in the combustion chamber and the mixing process with fuel and air, thus affecting the distribution of local temperature and oxygen concentration and determining the combustion conditions, which will affect the final NOx emission. As the fuel jet and air jet velocity ratio and fuel jet dip angle increase, the flue gas recirculation area expands in the combustion chamber, which intensifies the mixing of fuel, air and flue gas to expand the area of low oxygen and the maximum temperature and average The temperature is reduced, NOx production significantly reduced. The research results have certain reference meaning for the burner design of industrial furnace.