采用定容燃烧实验平台获得初始压力为0.1 MPa、初始温度为420、450 K和480 K,当量比为0.8~1.4工况下正十四烷/空气预混气层流燃烧速度和马克斯坦长度,并分析了初始温度、当量比等因素的影响。研究发现:初始温度和当量比的增加对预混气球形火焰稳定性影响较小,在初始温度为480 K、当量比为1.3工况下,火焰内部无裂纹或胞状结构;初始温度的增加能够加快火焰传播速度,促进火焰锋面形成,其影响在稀混合气中更为显著;随着当量比的增加,正十四烷预混燃烧火焰马克斯坦长度减小,火焰稳定性变差;随着初始温度的增加,正十四烷马克斯坦长度减小,无拉伸火焰传播速度和层流燃烧速度增加,另外,与RP-3航空煤油层流燃烧速度对比发现,正十四烷层流燃烧速度整体偏高。
The laminar burning velocity and Markstein length of n-tetradecane/air mixture were obtained under initial pressure of 0.1 MPa, initial temperatures of 420, 450 K and 480 K within a wide equivalence ratio range from 0.8 to 1.4 in a constant volume chamber, and the effects of initial temperature and equivalence ratio were analyzed. The results showed that the increase of initial temperature and equivalence ratio had little effect on the stability of the flame propagation images. Under the initial temperature of 480 K and equivalence ratio of 1.3, there was no crack or cellular structure in the flame. The effect that the increase of initial temperature can increase the flame propagation speed and promote the formation of flame front was observed, which was more significant in the lean mixture. With the increase of equivalence ratio, the Markstein length of n-tetradecane/air mixture decreased and the flame stability became worse. With the increase of temperature, the Markstein length decreased, and the unstretched flame speed and laminar burning velocity increased. In addition, compared with the laminar burning velocity of RP-3 kerosene, the laminar burning velocity of n-tetradecane was higher under most conditions.