Computational Analysis on the Effect of Methanol Energy Ratio on the Spray and Combustion Pattern of a Dual-Fuel Compression Ignition Engine

Abstract

Methanol is gaining significant attention for its potential in green energy production and its easy handling and storage. Using methanol in conjunction with diesel, under dual operation, does not require significant hardware adaptations (this is the case of methanol port fuel injection) and it enables the replacement of a fossil fuel with a low-carbon and oxygenated sustainable fuel. This work aims to analyze the impact of the methanol energy substitution ratio on a compression ignition engine running in dual mode with heptane and methanol. Numerical validations are conducted across four cases, i.e., 20%, 35%, 45%, and 55% methanol energy substitution ratio. Simulations are conducted with Eulerian–Lagrangian framework for which the continuous media is modeled using an Eulerian approach, though the dispersed phase (spray) is pursued following the former. Turbulence is governed using the renormalization group k–epsilon. Key parameters, incorporating spray characteristics, reaction zone distribution, and combustion behavior, are analyzed. The findings show that high methanol energy substitution values slow down the spray vaporization and affect the combustion pattern. At the lowest methanol energy substitution ratio (below 20%), flames originate at the periphery and move inward, while at higher ratios, flame starts near the spray region and spreads across the entire chamber. The ignition delay is extended with the rise of the methanol energy substitution ratio, though combustion duration decreases. Simulation results are compared against experimental data to ensure the validation of the entire global model.