Autoignition of iso-octane at ultra-lean and lean conditions

Khaiyom Hakimov, Yang Li, Mani Sarathy, Jihad Badra, Emre Cenker, Aamir Farooq

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Ignition delay times (IDTs) of iso-octane/air mixture were measured in a high-pressure shock tube and a rapid compression machine at ultra-lean (Φ = 0.2) to lean (Φ = 0.4 – 0.6) equivalence ratios, pressures of 20 – 40 bar, and temperatures of 630 – 1250 K. Measured IDTs were longer at lower equivalence ratio, and the equivalence ratio effect was most prominent in the intermediate temperature range. IDTs were shorter at higher pressures and, likewise, the dependence on pressure was maximum at intermediate temperatures. Predictions of existing chemical kinetic models were compared with the experimental data. Notable differences were observed between the model predictions and the newly obtained IDT data at fuel-lean conditions. Sensitivity analyses were performed to identify key reactions affecting fuel reactivity at various temperature regimes. Rate coefficients of two sensitive reactions, IC4H8+IC4H9↔AC8H17 and AC8H17O2↔AC8H16OOH-C, were modified to improve model performance at intermediate and low temperatures for fuel-lean conditions.
Original languageEnglish (US)
Pages (from-to)112515
JournalCombustion and Flame
StatePublished - Nov 30 2022

Bibliographical note

KAUST Repository Item: Exported on 2023-01-02
Acknowledgements: This paper is based on work supported by Saudi Aramco Research and Development Center FUELCOM program under Master Research Agreement Number 6600024505/01. FUELCOM (Fuel Combustion for Advanced Engines), is a collaborative research undertaking between Saudi Aramco and KAUST intended to address the fundamental aspects of hydrocarbon fuel combustion in engines, and develop fuel/engine design tools suitable for advance combustion modes. This work is partly funded by the “Aoxiang Research Start-up Fund” at Northwestern Polytechnical University allocated to Dr. Yang Li. The authors would like to gratefully acknowledge fruitful discussions with Dr. Manuel Monge Palacios of CCRC KAUST.


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