Development and Evaluation of the Predictive Capabilities of a Dual-Fuel Combustion Model with Methanol or Hydrogen in a Medium Speed Large Bore Engine

Abstract

<div class="section abstract"><div class="htmlview paragraph">To mitigate climate change, it is essential that sustainable technologies emerge in the transport industry. One viable solution is the use of methanol or hydrogen combined with internal combustion engines (ICEs). The dual-fuel technology in particular, in which a diesel pilot ignites port fuel injected methanol or hydrogen, is of great interest to transition from diesel engines to ICEs using purely these fuels. This approach allows for a significant portion of fossil diesel to be replaced with sustainable methanol or hydrogen, while maintaining high efficiencies and the possibility to run solely on diesel if required. Additionally, lower engine-out pollutant emissions (NOx, soot) are produced. Although multiple experimental research results are available, numerical literature on both fuels in dual-fuel mode is scarce. Therefore, this study aims to develop a multi-zone dual-fuel combustion model for engine simulations. The model incorporates and describes specific sub-models for ignition delay, and laminar and turbulent burning velocities, as traditional compression or spark ignition sub-models fail in dual-fuel mode. The predictive results of the simulation model are then compared to measurements, particularly, evaluating the accuracy in engine performance parameters such as in-cylinder pressure and temperature, ignition delay and combustion phasing. It was found that the simulation model predicts well the ignition delay, the in-cylinder pressure and temperature, and the heat release rate, except for the tail of the combustion where it systematically overestimates the end of combustion. To optimize the predictive simulation model further, investigation is required into the dual-fuel combustion mode, including the evolution of the flame entrainment area, dual-fuel combustion coupling terms, and heat released by each combustion mode during a combustion cycle.</div></div>