Ethanol Inhomogeneous Lean Combustion Under Different Ambient Temperatures and Pressures with Hydrogen Enrichment

ABSTRACT

The effects of different ambient temperatures and pressures on the combustion of hydrogen-enriched liquid ethanol spray were studied in a constant-volume vessel, using experimental and numerical methods. The inhomogeneous combustion experiment was conducted under ultra-lean conditions at an overall equivalence ratio of 0.3 (33% spray ethanol/67% premixed hydrogen). The spray and flame images and combustion pressures were obtained. The spray simulation models used were the RANS k-ε turbulence model, KH-RT model, and wall film interaction model. The experimental results showed that the inhomogeneous combustion of the liquid ethanol spray can be divided into two stages: a rapid-burning and a slow-burning stage. The slow-burning stage was sensitive to changes in ambient temperature and pressure. Combustion duration decreased with elevated pressure and declined temperature. Under low pressure and medium temperature conditions, the flame reached its fastest propagation speed. The simulation results showed that the fuel concentration and concentration gradient around the ignition position are the key factors that affect inhomogeneous lean combustion. When the equivalence ratio was over 0.8 around the ignition position and the gradient of the equivalence ratio increased no less than 0.1/mm, the optimal combustion characteristics were achieved.

KEYWORDS:

• Inhomogeneous combustion
• direct injection
• hydrogen enrichment
• constant volume vessel
• spray simulation

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contribution

Ruihan Ge: Methodology, Data curation, Writing original draft.

Erjiang Hu: Writing methodology, Writing, reviewing and editing.

Xin Lv: Data curation, Investigation.

Chenglong Tang: Investigation, Writing methodology.

Zuohua Huang: Supervision, Conceptualization, Writing, reviewing and editing.

Supplementary data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/00102202.2023.2295318.

Additional information

Funding

This study is supported by the National Science and Technology Major Project (J2019-III-0018-0062), the National Key Research and Development Program of China (2021YFA0716201), Natural Science Foundation of Shaanxi Province (2021JLM-18, 2020JC-04, 2023KXJ-228) and National Natural Science Foundation of China (51876163, 52176131).