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Large Eddy Simulation of Combustion Characteristics of Non-premixed Methane Jet with Pilot Diesel in High-Pressure Direct Injection Mode
ISSN: 1946-3952, e-ISSN: 1946-3960
Published January 13, 2022 by SAE International in United States
Citation: Zhou, L., Liu, Z., Zhao, W., Jiang, X. et al., "Large Eddy Simulation of Combustion Characteristics of Non-premixed Methane Jet with Pilot Diesel in High-Pressure Direct Injection Mode," SAE Int. J. Fuels Lubr. 15(1):99-118, 2022, https://doi.org/10.4271/04-15-01-0005.
The high-pressure direct injection (HPDI) mode can effectively reduce knock occurrence and improve engine thermal efficiency for the natural gas (NG)-diesel dual-fuel (DF) engine. To further understand the ignition process and flame stabilization, a large eddy simulation (LES) framework coupled with a detailed chemistry solver was conducted with variations in the pilot diesel mass and methane (CH4) injection timing. Different combustion regions are identified in the temperature versus equivalence ratio space. Results show that the pilot diesel-fuel mass ratio has a significant influence on the high-temperature diffusive combustion of CH4. By slightly increasing the pilot fuel mass, less CH4 is consumed in the non-premixed combustion mode. In addition, numerical results also imply that by prolonging the injection timing of CH4, more low-temperature species are produced by CH4 rather than by diesel. Besides, results show that methyl (CH3) can serve as a marker for high-temperature combustion of CH4 based on the formation region of CH3 and OH.