Ignition and combustion modelling in a dual fuel diesel engine

A numerical simulation of a single cylinder research diesel engine fuelled by natural gas and diesel oil in dual fuel mode was conducted to test the reaction mechanism presented by Li and Williams in Ref. [1] for methane ignition. The mechanism made of only 9 reactions can represent a good compromise between reduction of computational time and accuracy of results. Simulations reproduce test cases previously carried out experimentally and numerically with a simpler kinetic mechanism at three different premixed ratios (10%, 15% and 22%). Finally, a last case characterized by a supply of methane consistent with the typical load levels for this kind of engines (80%), was investigated only numerically. All the simulations were performed with the KIVA-3V solver on a geometry which includes open valve periods, intake and exhaust ducts. Through a comparison between experimental and numerical results, a calibration of the model has been performed and a quite good fitting of the models has been achieved.