The vitiation effects of water vapor and carbon dioxide on the autoignition characteristics of kerosene

• Published in: Acta mechanica Sinica Vol. 30; no. 4; pp. 485 - 494
• Main Authors: Liang, Jin-Hu, Wang, Su, Zhang, Sheng-Tao, Yue, Lian-Jie, Fan, Bing-Cheng, Zhang, Xin-Yu, Cui, Ji-Ping
• Format: Journal Article
• Language: English
• Published: Heidelberg The Chinese Society of Theoretical and Applied Mechanics; Institute of Mechanics, Chinese Academy of Sciences 01.08.2014
• Subjects: Classical and Continuum Physics; Computational Intelligence; Engineering; Engineering Fluid Dynamics; Research Paper; Theoretical and Applied Mechanics; 二氧化碳; 地面试验; 水蒸汽; 点火延迟时间; 煤油; 燃烧反应机理; 碳氢燃料; 自燃特性; Shock tube; Vitiation effect; Ignition delay; Kerosene water; Carbon dioxide
• ISSN: 0567-7718; 1614-3116
• DOI: 10.1007/s10409-014-0014-0

In ground tests of hypersonic scramjet, the highenthalpy airstream produced by burning hydrocarbon fuels often contains contaminants of water vapor and carbon dioxide. The contaminants may change the ignition characteristics of fuels between ground tests and real flights. In order to properly assess the influence of the contaminants on ignition characteristics of hydrocarbon fuels, the effect of water vapor and carbon dioxide on the ignition delay times of China RP-3 kerosene was studied behind reflected shock waves in a preheated shock tube. Experiments were conducted over a wider temperature range of 800-1 500 K, at a pressure of 0.3 MPa, equivalence ratios of 0.5 and 1, and oxygen concentration of 20%. Ignition delay times were determined from the onset of the excited radical OH emission together with the pressure profile. Ignition delay times were measured for four cases： （1） clean gas, （2） gas vitiated with 10% and 20% water vapor in mole, （3） gas vitiated with 10% carbon dioxide in mole, and （4） gas vitiated with 10% water vapor and 10% carbon dioxide, 20% water vapor and 10% carbon dioxide in mole. The results show that carbon dioxide produces an inhibiting effect at temperatures below 1 300 K when Ф = 0.5, whereas water vapor appears to accelerate the ignition process below a critical temperature of about 1 000 K when Ф = 0.5. When both water vapor and carbon dioxide exist together, a minor inhibiting effect is observed at Ф = 0.5, while no effect is found at Ф = 1.0. The results are also discussed preliminary by considering both the combustion reaction mechanism and the thermophysics properties of the fuel mixtures. The current measurements demonstrate vitiation effects of water vapor and carbon dioxide on the autoignition characteristics of China RP-3 kerosene at air-like O2 concentration. It is important to account for such effects when data are extrapolated from ground testing to real flight conditions.