Fundamental investigation of methanol flash boiling combustion under direct injection conditions

IF 5.8 2区工程技术 Q2 ENERGY & FUELS

Combustion and Flame Pub Date : 2025-03-30 DOI:10.1016/j.combustflame.2025.114147

Mingli Cui , Mohamed Nour , Jinhong Fu , Weixuan Zhang , Guodong Wang , Hongchang Xu , Bowei Yao , Xuesong Li

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引用次数: 0

Abstract

The task of reducing carbon emissions has become a primary goal for energy utilization purposes via combustion. The use of e-fuels/alternative fuels is a viable solution to enable zero carbon emission during the life cycle. However, the combustion of such fuels, such as methanol, is somehow different from combusting gasoline or diesel in the aspects of fuel atomization/evaporation and combustion mechanisms, etc. Flash boiling atomization is a promising atomization approach for improving the atomization and evaporation of alcohol fuels. The use of flash boiling atomization has been validated in optical gasoline direct injection (GDI) engines. However, the fundamental understanding of the impact of flash boiling on fuel combustion is still missing. This investigation focuses on the combustion of methanol fuel in a constant volume combustion chamber in a GDI fuel-air mixing fashion. The spray and flame propagation characteristics are obtained via high-speed imaging. Furthermore, detailed combustion product analysis is carried out using an online Fourier transform infrared (FTIR) device to distinguish the fundamental difference when combusting the fuel under sub-cooled and flash boiling conditions. Soot produced during the combustion is collected by mesh grids and analyzed via a transmission electron microscope (TEM). The results show that flash boiling promotes combustion efficiency under rich combustion conditions. Compared to sub-cooled combustion, methanol flash boiling combustion increases CO/CO2 emissions by 11.8 % and aldehydes emissions by 19.3 %, while reducing unburned hydrocarbons by approximately 30 %. NOx and aromatics emissions are decreased under methanol flash boiling combustion by 49.7 % and 55.1 %, respectively. Compared to n-heptane, methanol sub-cooled combustion reduces the production of soot particles. The stronger oxidation effect of methanol suppresses nuclei-mode soot generation, and the soot particles from methanol combustion feature shorter, more compact, and orderly stacked graphene layers. Moreover, flash boiling atomization further inhibits soot formation from methanol combustion.

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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.