Cylinder Lubrication of Two-Stroke Diesel Engines: Investigation of Nozzle Flow and Spray Formation using Numerical Simulation and Experimental Visualisation

Cylinder lubrication oil is an important component for the operation of large two-stoke marine diesel engines. It controls the mechanical friction loss and wear on cylinder liner and piston rings by providing a thin oil film between the sliding interfaces. The lubrication oil is injected as a spray into the scavenging air swirl inside the cylinder, thereby providing an even coverage of the oil at the top of the cylinder, where the need of lubrication is highest.

Over the last decades, there has been an increasing focus on optimising the lubrication oil consumption in order to reduce the operational costs of marine diesel engines. As of today, the analysis has been documented by an experimental trial and error approach. Numerical investigations of the spray injection process have not been performed in order to establish an understanding of the complex process. This PhD thesis will serve as a starting point for the investigations by covering the topics influencing the flow of cylinder lubrication oil through the injection nozzle and the subsequent spray formation.