A Dual-Fuel Model of Flame Initiation and Propagation for Modelling Heavy-Duty Engines with the G-Equation

2023 JSAE/SAE Powertrains, Energy and Lubricants International Meeting
Authors Abstract
We propose a novel dual-fuel combustion model for simulating heavy-duty engines with the G-Equation. Dual-Fuel combustion strategies in such engines features direct injection of a high-reactivity fuel into a lean, premixed chamber which has a high resistance to autoignition. Distinct combustion modes are present: the DI fuel auto-ignites following chemical ignition delay after spray vaporization and mixing; a reactive front is formed on its surroundings; it develops into a well-structured turbulent flame, which propagates within the premixed charge. Either direct chemistry or the flame-propagation approach (G- Equation), taken alone, do not produce accurate results. The proposed Dual-Fuel model decides what regions of the combustion chamber should be simulated with either approach, according to the local flame state; and acts as a “kernel” model for the G- Equation model. Direct chemistry is run in the regions where a premixed front is not present. The “kernel” front is identified using a fast, sparse Chemical Explosive Mode Analysis (CEMA), and a novel on-the- fly spontaneous flame speed formulation. The G=0 surface is initialized when the front is thick enough to be well-represented on the computational grid; it is then advanced using the G-Equation model with a multi-component flame speed. The model is validated against optical experiments which feature direct- injected Diesel and premixed natural gas. Good accuracy and reliability are seen identifying the flame initiation region, with little user input.
Meta TagsDetails
Perini, F., Wright, C., Reitz, R., Hiraoka, K. et al., "A Dual-Fuel Model of Flame Initiation and Propagation for Modelling Heavy-Duty Engines with the G-Equation," Advances and Current Practices in Mobility 6(3):1380-1392, 2024, https://doi.org/10.4271/2023-32-0009.
Additional Details
Sep 29, 2023
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Journal Article