A comprehensive experimental and modeling study of iso-pentanol combustion S. Mani Sarathy a,⇑ , Sungwoo Park a , Bryan W. Weber b , Weijing Wang c , Peter S. Veloo d , Alexander C. Davis a , Casimir Togbe e,1 , Charles K. Westbrook f , Okjoo Park g , Guillaume Dayma e , Zhaoyu Luo b , Matthew A. Oehlschlaeger c , Fokion N. Egolfopoulos g , Tianfeng Lu b , William J. Pitz f , Chih-Jen Sung b , Philippe Dagaut e a Clean Combustion Research Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia b Department of Mechanical Engineering, University of Connecticut, Storrs, CN, USA c Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA d Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ, USA e CNRS-INSIS, 1C, Ave de la Recherche Scientifique, Orleans Cedex 2, France f Lawrence Livermore National Laboratory, Livermore, CA, USA g Department of Aerospace and Mechanical Engineering, University of Southern California, Los Angeles, CA 90089, USA article info Article history: Received 14 May 2013 Received in revised form 17 June 2013 Accepted 18 June 2013 Available online 1 August 2013 Keywords: Combustion chemistry Chemical kinetic modeling Shock tube Rapid compression machine Jet stirred reactor Mechanism reduction abstract Biofuels are considered as potentially attractive alternative fuels that can reduce greenhouse gas and pol- lutant emissions. iso-Pentanol is one of several next-generation biofuels that can be used as an alterna- tive fuel in combustion engines. In the present study, new experimental data for iso-pentanol in shock tube, rapid compression machine, jet stirred reactor, and counterflow diffusion flame are presented. Shock tube ignition delay times were measured for iso-pentanol/air mixtures at three equivalence ratios, temperatures ranging from 819 to 1252 K, and at nominal pressures near 40 and 60 bar. Jet stirred reactor experiments are reported at 5 atm and five equivalence ratios. Rapid compression machine ignition delay data was obtained near 40 bar, for three equivalence ratios, and temperatures below 800 K. Laminar flame speed data and non-premixed extinction strain rates were obtained using the counterflow config- uration. A detailed chemical kinetic model for iso-pentanol oxidation was developed including high- and low-temperature chemistry for a better understanding of the combustion characteristics of higher alco- hols. First, bond dissociation energies were calculated using ab initio methods, and the proposed rate con- stants were based on a previously presented model for butanol isomers and n-pentanol. The model was validated against new and existing experimental data at pressures of 1–60 atm, temperatures of 650– 1500 K, equivalence ratios of 0.25–4.0, and covering both premixed and non-premixed environments. The method of direct relation graph (DRG) with expert knowledge (DRGX) was employed to eliminate unimportant species and reactions in the detailed mechanism, and the resulting skeletal mechanism was used to predict non-premixed flames. In addition, reaction path and temperature A-factor sensitivity analyses were conducted for identifying key reactions at various combustion conditions. Ó 2013 The Combustion Institute. Published by Elsevier Inc. All rights reserved. 1. Introduction The interest in alternative fuels and fuel additives has in- creased in recent years. Oxygenated fuels have been considered as alternative fuels in order to reduce NOx and particulate emissions. In addition, the production of oxygenated fuels from renewable sources can balance emissions of the major green- house gas (CO 2 ) from combustion devices. However, the fundamental combustion properties of oxygenated fuels need to be evaluated prior to application [1]. Ethanol is an attractive alternative bio-based alcohol fuel extender for petroleum fuels. Although ethanol can reduce the dependency upon petroleum fuels and thus greenhouse gas emissions, disadvan- tages such as high O/C ratio, high hygroscopicity, and low en- ergy density can cause problems with fuel storage, blending, and use in engines. On the other hand, higher alcohols have lower hygroscopicity and corrosivity, higher energy density, and can be readily blended with hydrocarbon fuels in fueling systems. 0010-2180/$ - see front matter Ó 2013 The Combustion Institute. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.combustflame.2013.06.022 ⇑ Corresponding author. E-mail address: mani.sarathy@kaust.edu.sa (S. Mani Sarathy). 1 Present address: Department of Chemistry, Bielefeld University, Bielefeld, Germany. Combustion and Flame 160 (2013) 2712–2728 Contents lists available at SciVerse ScienceDirect Combustion and Flame journal homepage: www.elsevier.com/locate/combustflame