【作者】 苟湘；

【导师】 吴晋湘；

【作者基本信息】 河北工业大学 ， 热能工程， 2003， 硕士

【摘要】 本文在天津市重点自然科学基金项目(高效低NO_X排放燃气燃烧器的研究开发)的资助下，对燃气燃烧的低NO_X排放完成了实验研究和数值模拟，为低NO_X燃气燃烧器的开发提供指导。 首先建立了完善灵活的低NO_X燃烧实验系统，在实验系统上完成了燃烧温度、过量空气系数、预先加入一定量的水蒸汽、空气预热温度、对燃气预先进行微波处理、烟气再循环燃烧以及燃烧方式(扩散式与预混式)对NO_X生成的影响分析；采用PHOENICS 3.5软件进行了液化石油气燃烧的数值模拟。 本文通过实验得出了燃烧室出口NO_X的浓度随燃烧室出口温度的增加而增加。首次发现当过量空气系数低于0.75时，NO_X的生成量急剧增大。对目前普遍认为的分级燃烧和浓淡燃烧可以降低NO_X排放的提法给予补充，即对一次过量空气系数有一个最小值限定，不是小于1的任何值都可以，低于最小限定值将是不利的，而且一次过量空气系数有一个最佳值。最小值和最佳值要依据燃料而定。首次发现在燃气燃烧以前预加入少量水蒸汽能降低70％以上的NO_X排放，同时也大大降低CO和CH的排放。得出燃烧室出口NO_X的浓度随预热空气温度的增加而增加。发现经过微波处理后的燃烧能得到较可观NO_X浓度的降低。利用特殊设计的烟气再循环式燃气燃烧器做实验，发现得到较低的NO_X排放。利用PHOENICS3.5模拟出的燃烧室温度场和NO_X浓度场基本能说明实际分布状况。更多还原

【Abstract】 Supported by the Important Natural Science Foundation of Tianjin (Research and Development of Low NOx Emission of Gas Burners with High Efficiency ), experimental investigation and numerical simulation of low NOx emission in gas combustion are accomplished in this paper, which provides guidance for the development of low NOx emission of gas burners.In this paper a perfect and flexible experimental system of low NOx combustion is established firstly. The influences of the temperature of combustion, the air excess coefficient , a certain amount of vapor added in advance, the temperature of preheated air, adding microwave into gas before combustion, gas recycling combustion and the mode of combustion (diffused and premixed) on NOx emission are analyzed respectively. The combustion of Liquid Petroleum Gas is simulated with PHOENICS 3.5.The NOx concentration increases with the temperature of outlet of the combustion chamber. It is firstly found that the NOx concentration increases rapidly when is less than 0.75, which complements the staged combustion and the rich-lean combustion that are well considered currently as low NOx combustion. It does not mean that the combustion must be the low NOx combustion when <1. There is a limited least value of air excess coefficient. The combustion is not the low NOx combustion when is less than the limited least value. There is a perfect in the first stage combustion which is determined by the properties of fuel. It is firstly found that the amount of NOx emission can reduce by more than 70% and the amount of CH, CO emission also can reduce greatly when a certain amount of vapor is added into the air and/or gas system before combustion. The NOx concentration of the outlet of the combustion chamber increases with the temperature of preheated air. It is firstly found that the NOx concentration decreases greatly when adding microwave into gas before combustion. The lower NOx combustion generates when the special designed gas reburning burner is used in the experiment. The temperature distribution and the distribution of NOx concentration are achieved by PHOENICS 3.5, which can describe the practical situation.更多还原