Parametric optimisation of diesel–methanol injection timings of a dual-fuel marine engine operating with high methanol fraction using CFD

Tools

Karvounis, Panagiotis and Theotokatos, Gerasimos (2025) Parametric optimisation of diesel–methanol injection timings of a dual-fuel marine engine operating with high methanol fraction using CFD. Applied Thermal Engineering, 264. 125433. ISSN 1359-4311 (https://doi.org/10.1016/j.applthermaleng.2025.1254...)

[thumbnail of Karvounis-Theotokatos-ATE-2025-Parametric-optimisation-of-diesel�methanol-injection-timings-of-a-dual-fuel-marine-engine]
Preview
 Text. Filename: Karvounis-Theotokatos-ATE-2025-Parametric-optimisation-of-diesel_methanol-injection-timings-of-a-dual-fuel-marine-engine.pdf
Final Published Version
License: Creative Commons Attribution 4.0 logo
Download (7MB)| Preview

Abstract

Although methanol is a transition fuel to decarbonise the shipping industry, its wider use is hindered by several challenges including the dual fuel combustion of high methanol fractions in marine engines. This study aims to parametrically optimise the injection settings for a large marine four-stroke dual-fuel engine of 10.5 MW nominal power considering three representative loads of the operating envelope. The closed cycle of one engine cylinder is modelled in CONVERGE. The CFD model for the diesel mode is first developed and subsequently extended for the dual fuel (methanol–diesel) mode considering 90 % methanol energy fraction. The model is validated against experimental data for the engine diesel and dual fuel operation. Parametric runs with different methanol and pilot diesel injection timings are conducted to identify the settings that achieve the objectives of increased thermal efficiency and reduced NOx emissions considering the constraints pertaining to stable combustion conditions. Results indicate that injecting methanol during the compression stroke (80oCA BTDC) and diesel at (12oCA BTDC) achieves combustion efficiency up to 99 % and indicated thermal efficiencies of 46 %, 45 %, and 43 % for high, medium, and low loads, respectively, whilst compiling with IMO Tier III limits for NOx emissions. The novelty of the study lies in the setup of a widely applicable CFD model for methanol fuelled marine engines; compliance with IMO Tier III limits and identification of the optimal injection timings ensuring combustion stability, reducing NOx emissions, and improving thermal efficiency. The study provides insights for the development of methanol fuelled marine dual fuel engines.

ORCID iDs

Karvounis, Panagiotis and Theotokatos, Gerasimos ORCID logoORCID: https://orcid.org/0000-0003-3547-8867;
CORE (COnnecting REpositories)