Autoignition of Toluene and Benzene at Elevated Pressures in a Rapid Compression Machine

Abstract Autoignition of toluene and benzene is investigated in a rapid compression machine at conditions relevant to HCCI (homogeneous charge compression ignition) combustion. Experiments are conducted for homogeneous mixtures over a range of equivalence ratios at compressed pressures from 25 to 45 bar and compressed temperatures from 920 to 1100 K. Experiments varying oxygen concentration while keeping the mole fraction of toluene constant reveal a strong influence of oxygen in promoting ignition. Additional experiments varying fuel mole fraction at a fixed equivalence ratio show that ignition delay becomes shorter with increasing fuel concentration. Moreover, autoignition of benzene shows significantly higher activation energy than that of toluene. In addition, the experimental pressure traces for toluene show behavior of heat release significantly different from the results of Davidson et al. [D.F. Davidson, B.M. Gauthier, R.K. Hanson, Proc. Combust. Inst. 30 (2005) 1175–1182]. Predictability of various detailed kinetic mechanisms is also compared. Results demonstrate that the existing mechanisms for toluene and benzene fail to predict the experimental data with respect to ignition delay and heat release. Flux analysis is further conducted to identify the dominant reaction pathways and the reactions responsible for the mismatch of experimental and simulated data.

[1]  C. Sung,et al.  Determination of laminar flame speeds using digital particle image velocimetry: Binary Fuel blends of ethylene, n-Butane, and toluene , 2002 .

[2]  R. Sivaramakrishnan,et al.  A high pressure model for the oxidation of toluene , 2004 .

[3]  Raghu Sivaramakrishnan,et al.  High-pressure, high-temperature oxidation of toluene , 2004 .

[4]  R. A. Matula,et al.  Comparative ignition delay times for selected ring-structured hydrocarbons , 1979 .

[5]  William J. Pitz,et al.  Detailed chemical kinetic reaction mechanisms for autoignition of isomers of heptane under rapid compression , 2002 .

[6]  Chung King Law,et al.  Laminar flame speeds and oxidation kinetics of benene-air and toluene-air flames , 1996 .

[7]  R. Hanson,et al.  Investigation of the reaction of toluene with molecular oxygen in shock-heated gases , 2006 .

[8]  H. Olivier,et al.  Ignition of shock-heated H2-air-steam mixtures , 2003 .

[9]  Ronald K. Hanson,et al.  Shock tube ignition measurements of iso-octane/air and toluene/air at high pressures , 2005 .

[10]  R. P. Lindstedt,et al.  Detailed Kinetic Modelling of Toluene Combustion , 1996 .

[11]  R. Minetti,et al.  Oxidation and combustion of low alkylbenzenes at high pressure: Comparative reactivity and auto-ignition , 2000 .

[12]  Shigeyuki Tanaka,et al.  A reduced chemical kinetic model for HCCI combustion of primary reference fuels in a rapid compression machine , 2003 .

[13]  William J. Pitz,et al.  Ignition of Isomers of Pentane: An Experimental and Kinetic Modeling Study , 2000 .

[14]  J. L. Emdee,et al.  A kinetic model for the oxidation of toluene near 1200 K , 1992 .

[15]  S. Davis,et al.  Determination of and Fuel Structure Effects on Laminar Flame Speeds of C1 to C8 Hydrocarbons , 1998 .

[16]  Hugh W. Coleman,et al.  Experimentation and Uncertainty Analysis for Engineers , 1989 .

[17]  F. Battin‐Leclerc,et al.  Experimental and modeling study of the oxidation of toluene , 2005 .

[18]  Chih-Jen Sung,et al.  Aerodynamics inside a rapid compression machine , 2006 .

[19]  Chih-Jen Sung,et al.  A RAPID COMPRESSION MACHINE FOR CHEMICAL KINETICS STUDIES AT ELEVATED PRESSURES AND TEMPERATURES , 2007 .

[20]  Richard A. Yetter,et al.  Autoignition of H2/CO at elevated pressures in a rapid compression machine , 2006 .

[21]  R. Minetti,et al.  Experimental study of the kinetic interactions in the low-temperature autoignition of hydrocarbon binary mixtures and a surrogate fuel , 2006 .

[22]  Stephen D. Klotz,et al.  Modeling the combustion of toluene-butane blends , 1998 .

[23]  A. Ristori,et al.  Oxidation, ignition and combustion of toluene: Experimental and detailed chemical kinetic modeling , 2002 .