Modelling the Combustion Process of Marine Diesel Engines to Reduce Pollutant Emissions and Influence Vibrations at the Propeller Shaft for a Bulk Carrier Vessel

The modeling of the combustion process in internal combustion engines has always been a major concern for experts in the field. The complex nature of the phenomena involved and their strong interdependencies make the approach particularly challenging. The implementation of the provisions outlined in the 1997 Protocol's Annex 6, which aimed at limiting pollutant emissions from ships, especially nitrogen oxides, has been a significant focus for signatory countries since 2010. Coastal areas, particularly those frequented by port technical vessels, have been identified as the most affected regions. From the technical documentation of the ship received on board the ship in the design phase, the following values were calculated: actual diameter of the intermediate shaft 387.2 mm adopting 420 mm, actual bore diameter of 472.4 mm adopting 500 mm, flange thickness coupling 77.4 mm, adopted 100 mm, calculated radius of thread at the base of the 33.6 mm coupling flanges adopted 70 mm, actual diameter of the 46.6 mm flange shaft flange bolts, adopted 64 mm. The ship's propeller has four fixed-pitch blades and a weight of 31.42 tons. Furthermore, torsional vibrations, tree alignment calculations, torsional vibration calculations, critical vibrations, propeller design calculations were calculated in the project. As can be seen from the simulation results, the front-wheel resonance is 155% of the maximum engine speed (127.0 rpm) and the critical resonance is 133% of the maximum engine speed. The result of the spin calculation is therefore acceptable and is not expected to occur at the speed of the engine.