Numerical study of a marine dual-fuel four-stroke engine

摘要

Continuously increasing environmental demands in conjunction with the planned strong penetration of the LNG, render the use of LNG as an attractive alternative marine fuel. In this framework, the traditional ship propulsion plants based on Diesel engines running with HFO, should be revisited and compared to the more efficient and environmentally friendly propulsion systems that use dual fuel engines. The present study deals with the computational investigation of a marine four-stroke dual fuel (DF) engine, in both diesel and DF mode operation. The engine model was set up in a commercial software and used to compare the performance and emissions of the investigated engine operation at steady state conditions. The engine diesel mode was initially set up and the model was calibrated to adequately represent the engine operation. Subsequently, the engine dual fuel model was set up by considering the injection of two different fuels; methane and pilot diesel fuel. The derived results were analysed for revealing the differences of the engine performance and emissions at each engine mode. In addition, the turbocharger matching at each mode is investigated revealing the challenges due to the completely different air-fuel ratio strategies used in diesel and dual fuel modes, respectively.