An experimental and modeling study of iso-octane ignition delay times under homogeneous charge compression ignition conditions
- Department of Mechanical Engineering, University of Michigan, 2350 Hayward Street, Ann Arbor, MI 48109-2125 (United States)
Autoignition of iso-octane was examined using a rapid compression facility (RCF) with iso-octane, oxygen, nitrogen, and argon mixtures. The effects of typical homogeneous charge compression ignition (HCCI) conditions on the iso-octane ignition characteristics were studied. Experimental results for ignition delay times, t{sub ign}, were obtained from pressure time-histories. The experiments were conducted over a range of equivalence ratios (f=0.25-1.0), pressures (P=5.12-23 atm), temperatures (T=943-1027 K), and oxygen mole fractions ({chi}{sub O{sub 2}}=9-21%), and with the addition of trace amounts of combustion product gases (CO{sub 2} and H{sub 2}O). It was found that the ignition delay times were well represented by the expression t{sub ign}=1.3x10{sup -4}P{sup -1.05}f{sup -0.77}{chi}{sub O{sub 2}}{sup -1.41}exp(33,700/R{sub (c} {sub al/mol/K)}T), where P is pressure (atm), T is temperature (K), f is the equivalence ratio (based on iso-octane to O{sub 2} molar ratios), {chi}{sub O{sub 2}} is the oxygen mole percent (%), and t{sub ign} is the ignition delay time (ms). Carbon dioxide was found to have no chemical effect on t{sub ign}. Water was found to systematically decrease t{sub ign} by a small amount (less than 14% for the range of conditions studied). The maximum uncertainty in the measured t{sub ign} is +/-12% with an average uncertainty of +/-6%. The performance of several proposed chemical reaction mechanisms (including detailed, reduced, and skeletal mechanisms) was evaluated in the context of the current experimental results.
- OSTI ID:
- 20677691
- Journal Information:
- Combustion and Flame, Vol. 142, Issue 3; Other Information: Elsevier Ltd. All rights reserved; ISSN 0010-2180
- Country of Publication:
- United States
- Language:
- English
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