废气再循环成分对扩散燃烧中碳烟成核的影响

Study on the effect of the EGR species on soot nucleation in diffusion flames

通过测量对置射流扩散火焰中开始形成碳核时的临界气动变形率 KP,对空气中加入燃烧废气(CO2 和 N2 )时的乙烯和丙烷的扩散火焰中碳烟成核的影响进行了实验研究 .通过适当的火焰温度调节方法 ,将 CO2 对碳烟成核过程所起的各种作用进行了分解 ,并由此得出结论 :CO2 对扩散火焰具有遏制碳烟成核的作用 .

EGR as a measure to reduce diesel engine NO\-2 emission would brought a counteracting effect on the soot emission of the engine. An experimental study on EGR'S effect, on the soot formation in diffusion flames was conducted by measuring the soot inception limits \%K\-P\%, which was used as the criteria of the flame's sooting tendency. EGR might affect soot formation in the diffusion flames formed in a counter flow burner set in the follow ways: change the oxygen concentration of the air, change the flame temperature, and the chemical effect of the added species of CO\-2. To investigat how these factors affected soot formation, the anthor used the inert substitute technique of substituting an appropriate part of N\-2 in the air by the same mole fraction of less specific heat species, Ar, to maintain the flame temperature equal to that of original flame formed by the same fuel with the air with EGR. The results showed that the CO\-2 addition suppressd the soot inception in the diffusion flames. Oxygen concentration has basically the some effect as that of flame temperature.