Numerical study of lubricant film combustion characteristics under ammonia and ethylene premixed environment

In response to dual-carbon targets, zero-carbon, and low-carbon alternative fuel engines are increasingly in demand. In zero-carbon, low-carbon fuel engines, the lubricating oil is the major contributor to soot emissions. In this study, three-dimensional CFD simulations were adopted to investigate the combustion characteristics of lubricant film in an ammonia and ethylene-premixed environment. The effects of flame development direction, film thickness, and different ethylene ratios on the lubricant combustion process were investigated. The results indicated that the effect of flame direction on fuel consumption and heat release fluctuations, the role of film thickness in modifying heat transfer and evaporation rates, and the spatial distribution of combustion products. In addition, the effects of boundary conditions on soot generation and distribution and the complex interactions between physical and chemical processes in lubricant film combustion were characterized. This study provided new insights into the thermodynamic and chemical transformations of lubricant films under different combustion conditions, contributing to a better understanding of the generation of atmospheric pollutants from low-carbon fuels.