Numerical modelling and analysis of the ambient conditions influence on the performance of a marine diesel engine

The paper reports the results of a study concerning the influence of ambient conditions on the performance of a marine diesel engine. Starting from the availability of a code previously developed for the thermodynamic simulation of the four-stroke marine engine General Electric 12 V 228, used as prime mover of a marine propulsion system, it was possible to determine the performance of the engine, running in the operating conditions existing in the ship’s engine room, for different ambient and seawater temperature values. The correlation between ambient and engine room conditions was assumed on the base of data available in literature. As regards the sea water temperature, which is not strictly dependent on that of the ambient air, in the final part of the paper a sensitivity analysis is reported on the influence of this parameter on engine performance. The analysis carried out allows to obtain the variation of the performance of the engine and its main components (turbocharger compressor and turbine, cylinders, inlet and exhaust manifolds, intercooler, etc.), as function of the ambient conditions and for different engine loads. The results of this investigation are reported in graphical form and discussed in the paper.