【摘要】 通过在实验与数值模拟下对不同预混度、气氛、燃气流量和环境温度对天然气火焰NOx生成的影响分析。研究结果表明:在空气气氛下,NOx排放随燃气流量的增大而单调增大,完全预混燃烧时NOx排放最低,完全扩散燃烧时NOx排放最高,而在部分预混燃烧时存在一个NOx排放次低点,其预混程度大约为50%~60%。其中,热力型NOx形成规律与总NOx形成规律相似,而快速型NOx大概占总NOx的10%~20%,随预混程度增大而递减。在增氧气氛下(>21%O2与N2),NOx随O2浓度的提高而成倍增加,其中,快速型NOx增长缓慢,热力型NOx大幅增加。同时,NOx的形成直接受环境温度影响,在一定温度范围内NOx的生成量与环境温度成二次函数的关系。更多还原

【Abstract】 This paper carried out the impact of premixed degree,oxygen concentrations,gas flow rate and environment temperature on the combustion of natural gas by experiments and numerical simulations.The results reveal that under air condition,NOx production increases monotonically with the increase of gas flow rate.NOxreaches a minimum in production under complete premixed condition,and a maximum in non-premixed condition.A second maximum is also observed at a partially premixed condition(the premixed degree is about 50% to60%).For these cases,the formation pattern of thermal NOxbetter fits the formation of total NOx.Prompt NOx makes up for 10% ~20% of the total NOx and decreases with increasing gas mixed degree.Under oxygen-rich conditions,NOxproduction increases in folds as O2 concentration increases.While the production of prompt NOxincreases slowly,thermal NOx increases quickly.Also,NOxformation is affected directly by the environmental temperature.Within a certain temperature range,NOxemission shows quadratic function-like relationship with environmental temperature.更多还原