A comparative study on the effects of NO2 addition on the auto-ignition behavior of n-heptane, iso-octane and toluene at engine relevant conditions

IF 5.8 2区工程技术 Q2 ENERGY & FUELS

Combustion and Flame Pub Date : 2025-03-23 DOI:10.1016/j.combustflame.2025.114118

Shijun Dong , Da Yao , A. Abd El-Sabor Mohamed , Jinhua Li , Wenxue Gao , Yang Cao , Zhaowen Wang , Jinhu Liang , Henry J. Curran , Xiaobei Cheng

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引用次数: 0

Abstract

It is necessary for gasoline surrogate models to simulate the effect of NOx addition on fuel auto-ignition behavior, as NOx can affect engine combustion via exhaust gas recirculation (EGR). Toluene is often used as a representative aromatic component in gasoline surrogate models, and hence it is important to investigate the effect of NOx addition on its auto-ignition behavior and to fully understand the interaction chemistry between toluene and NOx. In this paper, high-pressure shock tubes and a rapid compression machine are used to measure the ignition delay times (IDTs) of toluene in ‘air’ mixtures with and without the addition of nitrogen dioxide (NO₂), at a pressure of 20 atm and at temperatures in the range 600–1400 K. The IDTs of n-heptane, iso-octane and a mixture of toluene/n-heptane/iso-octane are measured at the same conditions for comparison. The experimental results show that the auto-ignition behavior of toluene exhibits significantly different sensitivity to NO₂ addition compared to n-heptane and iso-octane. NO₂ significantly promotes the reactivity of toluene at low temperatures (600–1000 K), in which the IDTs decreased by two orders of magnitude when 1000 ppm of NO₂ is added, whereas there is an order of magnitude decrease with the addition of 200 ppm NO₂. The promoting effect of NO₂ on toluene oxidation reduces significantly at temperatures above 1000 K. The experimental results also show that NO₂ addition exhibits a slight promoting effect on the reactivity of n-heptane and iso-octane at temperatures above 750 K at the conditions studied. A kinetic model is proposed based on C3MechV3.3 in which the interaction chemistry between these gasoline surrogates and NOx is updated. The proposed kinetic model can simulate well the effect of NO₂ addition on the auto-ignition behavior of these surrogates. Flux and sensitivity analyses are performed to highlight the important interaction reaction pathways.

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来源期刊

Combustion and Flame 工程技术-工程：化工

CiteScore

9.50

自引率

20.50%

发文量

631

审稿时长

3.8 months

期刊介绍： The mission of the journal is to publish high quality work from experimental, theoretical, and computational investigations on the fundamentals of combustion phenomena and closely allied matters. While submissions in all pertinent areas are welcomed, past and recent focus of the journal has been on: Development and validation of reaction kinetics, reduction of reaction mechanisms and modeling of combustion systems, including: Conventional, alternative and surrogate fuels; Pollutants; Particulate and aerosol formation and abatement; Heterogeneous processes. Experimental, theoretical, and computational studies of laminar and turbulent combustion phenomena, including: Premixed and non-premixed flames; Ignition and extinction phenomena; Flame propagation; Flame structure; Instabilities and swirl; Flame spread; Multi-phase reactants. Advances in diagnostic and computational methods in combustion, including: Measurement and simulation of scalar and vector properties; Novel techniques; State-of-the art applications. Fundamental investigations of combustion technologies and systems, including: Internal combustion engines; Gas turbines; Small- and large-scale stationary combustion and power generation; Catalytic combustion; Combustion synthesis; Combustion under extreme conditions; New concepts.