In-Nozzle Flow and Primary Breakup Investigations of Marine Two-Stroke Diesel Engine Injectors

Abstract: This thesis will focus on the experimental studies of in-nozzle flow and primary breakup of pressure-atomized fuel sprays as used in large marine two-stroke Diesel engines. To further increase the efficiency of large marine two-stroke Diesel engines, a better understanding of the fuel spray atomization process is necessary. Previous work has shown that the cavitating in-nozzle flow of fuel injectors significantly influences the primary breakup and atomization. Spray deflections have been observed which can lead to cylinder wall wetting resulting in increasing fuel consumption, emissions, component temperatures and loss of lubrication film. Large marine Diesel engines have different nozzle designs compared to light and heavy duty internal combustion engines and the research is not fully congruent. Additionally, there are no reference experiments for large marine two-stroke Diesel engines. To gather experimental data for validation of CFD codes and predictive spray models, this work presents the development of experimental equipment and acquisition of optical measurements to further investigate the influence of in-nozzle flow on the primary breakup of fuel injection sprays of large marine two-stroke Diesel engines.