采用实验研究的方法探讨了反应物预热温度与稀释率两个因素对稀释燃烧火焰稳定性的影响.实验以氮气稀释的甲烷-空气对冲扩散火焰为研究对象,确定了不同反应物预热温度与氧化剂稀释率(氧气体积分数)时火焰的熄火极限,结果表明,增大反应物预热温度拓宽了火焰稳定燃烧区域,而增加氧化剂稀释率(降低氧气体积分数)会降低稀释火焰的稳定性,二者对火焰稳定性的影响作用相反.为了进一步分析反应物预热温度与稀释率对火焰稳定性的影响程度,引入了估算的Damk hler数,分析表明,在实验研究范围内,反应物预热温度对火焰稳定性的影响比稀释率的影响显著,是火焰稳定性的主要影响因素. The influence of preheating temperature and dilution rate on the stability of dilute combustion flame was investigated by means of experimental study.The experiment was conducted on the methane-air heaped diffusion flame diluted with nitrogen gas, and the effects of preheating temperature And the oxidant dilution rate (oxygen volume fraction), the results show that increasing the reactant preheating temperature broadens the flame stable combustion zone and increasing the oxidant dilution rate (reducing the oxygen volume fraction) reduces the stability of the dilution flame , Which have the opposite effect on the flame stability.In order to further analyze the degree of influence of the reactant preheating temperature and the dilution rate on the flame stability, the estimated Damk hler number is introduced. The analysis shows that within the experimental range, the reactants The effect of preheating temperature on flame stability is more significant than dilution rate, which is the main factor of flame stability.