Investigations on the effects of low temperature reforming of n-heptane/n-butanol blends on the flame development progress and combustion chemical kinetics. (15th April 2021)

• Record Type: Journal Article
• Authors: Cui, Yanqing; Geng, Chao; Liu, Haifeng; Zheng, Zunqing; Wang, Qianlong; Yao, Mingfa
• Is Part Of: Fuel. Volume 290(2021)
• Publication Date: 2021-04-15
• Subjects: Low temperature reforming -- Optical diagnostic -- Gas chromatograph -- N-heptane -- N-butanol; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2020.120001
• Languages: English
• ISSNs: 0016-2361

Abstract

Highlights: The single-fuel RCCI can be realized through low temperature reforming (LTR). The LTR products of n-heptane/n-butanol can regulate the ignition timing. Most of the LTR products can delay the ignition timing. Small parts of the LTR products can advance the ignition timing. Abstract: The effects of low temperature reforming (LTR) of n-heptane/n-butanol blends on the flame development progress and combustion characteristic were investigated in an optical engine. The reforming temperatures were set as 423 K, 523 K and 623 K. Three n-heptane/n-butanol blending mixtures with volume fractions of n-butanol of 30% (B30), 50% (B50) and 70% (B70) were utilized. The detection, experiment and simulation methods included the gas chromatograph (GC) detection, high-speed imaging and chemical kinetics calculation. The main results are the following. Firstly, the LTR products were initially detected by the GC system. With the reforming temperature increasing, the mole fractions of aldehydes decrease. With the volume fraction of n-butanol increasing, the mole fractions of carbon monoxide, methanol and aldehydes increase while other species decrease. Secondly, the LTR products combined with the direct-injected fuel were introduced into the optical engine. For B30 and B50, the combustion phasing delays with the reforming temperature increasing. For B70, the combustion phasing initially advances and then delays with the reforming temperature increasing. Thirdly, the chemical kinetics simulation shows that most of the LTR products can decrease the mixture reactivity and delay the ignition timing, while small parts of the LTR products have the opposite effects.