Computational investigation of a large containership propulsion engine operation at slow steaming conditions

• Published in: Applied energy 2014-10, Vol.130, p.370-383
• Main Authors: Guan, Cong, Theotokatos, Gerasimos, Zhou, Peilin, Chen, Hui
• Format: Article
• Language: English
• Subjects: Applied sciences; Compressor performance map extension; Cycle mean value engine modelling; Electric driven blower operation; Energy; Energy. Thermal use of fuels; Engines and turbines; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Large containership propulsion engine; Slow steaming; Turbocharger cut-out
• ISSN: 0306-2619; 1872-9118
• DOI: 10.1016/j.apenergy.2014.05.063

•Extension of the compressor map towards the low speed region using a novel way.•Incorporation of the new compressor model and a blower submodel to the MVEM tool.•In-depth study of large two-stoke marine diesel engine operation at low load region.•Comparison of blower activation and turbocharger cut-out alternatives.•Blower can be activated in engine load below 25% if one turbocharger is cut-out. In this article, the operation of a large containership main engine was investigated with emphasis at slow steaming conditions. A cycle mean value approach implemented in the MATLAB/Simulink environment was adopted to simulate the two-stroke marine diesel engine due to the fact that it combines simplicity with adequate prediction accuracy. For accurately representing the compressor performance when the engine operates at low loads, the extension of the compressor map at the low rotational speed region was carried out based on a non-dimensional parameters method incorporating a novel way of calculating the compressor isentropic efficiency. The compressor map extension method results were validated using a corrected similarity laws approach. The engine steady state operation for various loads was simulated and the predicted engine performance parameters were validated using shop trial measurements. Furthermore, the engine transient operation in the load region below 50% was studied and the simulation results including the compressor operating points trajectory are presented and discussed. Based on the obtained results, the influence of the activation/deactivation of the installed electric driven blowers and the turbocharger cut-out on the engine operation was analysed.