CFD Modeling and Experimental Spray Studies for Different Heavy Fuel Oil Qualities with Respect to Large Two-Stroke Marine Engines

Abstract

Heavy fuel oil (HFO) is the predominant marine fuel. In the present study, a detailed model of HFO thermophysical properties, recently developed by the authors, is utilized for extensive computational fluid dynamics (CFD) studies of HFO spray dynamics in a large spray combustion chamber (SCC) and in a large marine engine; results are compared against existing and new experiments, for two HFO qualities. Here, spray modeling is based on a proper adaptation of the cascade atomization and drop break-up (CAB) model, whereas a new kinetic model accounting for HFO aromaticity is used for ignition modeling. Computational results are reported for nonreactive and reactive spray flow in the SCC, and are in good agreement with experimental data. The effects of HFO preheating on spray development are demonstrated. Finally, simulation results in a large marine engine are in good agreement with experiments in terms of pressure, heat release rate, and pollutant emissions. Overall, the present modeling is shown to be appropriate for detailed CFD studies of HFO spray flow and combustion in marine engines.