Free-spray characteristics and spray-wall interactions of methanol on a gasoline direct injector under flash-boiling and non-flash-boiling conditions

Lien HP, Clemente Mallada R, Dhanji M, Torelli R, Pickett LM (2026)

Publication Type: Journal article

Publication year: 2026

Journal

International Journal of Multiphase Flow Elsevier

Book Volume: 196

Article Number: 105562

DOI: 10.1016/j.ijmultiphaseflow.2025.105562

Abstract

Methanol is considered a promising alternative fuel for internal combustion engines (ICEs) due to its high-octane number, fast laminar flame speed, and elevated latent heat of vaporization, all of which support higher compression ratios and improved thermal efficiency. However, its substantial latent heat of vaporization also poses cold-start challenges, such as misfire and fuel film deposition. This study aims to investigate methanol spray morphology and spray-wall interaction using the Spray M injector from the Engine Combustion Network within a constant-pressure flow vessel. A recently developed unified numerical framework capable of modeling both flash and non-flash boiling sprays is validated against experimental liquid volume fraction data acquired via 3-D computed tomography. The results reveal that flash boiling significantly alters the spray morphology, leading to smaller droplets and spray collapse due to enhanced air-entrainment-induced turbulence. Quantitative agreement between experiments and simulations confirms this behavior. Coupled 0-D equilibrium and 3-D computational fluid dynamics analyses show that flash boiling accelerates evaporation and reduces fuel residence time, while non-flash conditions maintain a persistent liquid core more susceptible to wall wetting. Wall temperature diagnostics reveal that spray collapse alters heat transfer patterns by shifting cooling effects. Mixture fraction analysis indicates that evaporation is primarily governed by shear-layer turbulence, though deviations from adiabatic equilibrium mixing emerge under low-turbulence conditions. Finally, increasing fuel, ambient, and wall temperatures reduces wall wetting and film thickness, mitigating cold-start risks. These findings enhance the understanding of methanol sprays’ behavior and support its adoption as a viable, alternative fuel for ICEs.

Authors with CRIS profile

Rafael Clemente Mallada Professur für Fluidsystemtechnik

Involved external institutions

Argonne National Laboratory US United States (USA) (US) Sandia National Laboratories US United States (USA) (US)

How to cite

APA:

Lien, H.P., Clemente Mallada, R., Dhanji, M., Torelli, R., & Pickett, L.M. (2026). Free-spray characteristics and spray-wall interactions of methanol on a gasoline direct injector under flash-boiling and non-flash-boiling conditions. International Journal of Multiphase Flow, 196. https://doi.org/10.1016/j.ijmultiphaseflow.2025.105562

MLA:

Lien, Hao Pin, et al. "Free-spray characteristics and spray-wall interactions of methanol on a gasoline direct injector under flash-boiling and non-flash-boiling conditions." International Journal of Multiphase Flow 196 (2026).

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