Numerical Investigation of the Ignition Delay and Laminar Flame Speed for Pilot-Ignited Dual Fuel Engine Operation with Hydrogen or Methanol

The use of renewable fuels such as hydrogen and methanol in marine engines is a promising way to reduce greenhouse gas emissions from maritime transport. Hydrogen and methanol can be used as the main fuel in dual-fuel engines. However, the co-combustion of hydrogen-diesel and methanol-diesel needs to be carefully studied. In the present work, the ignition delay (ID) and laminar burning velocity (LBV) for pilot-ignited dual fuel engine operation with hydrogen or methanol are studied. A constant volume batch reactor numerical setup is used in the open source Cantera code to calculate the effect of the premixed fuel on the ID of the pilot fuel. Also, Cantera is used to simulate a freely-propagating, adiabatic, 1-D flame to estimate the laminar flame speed of either hydrogen or methanol and how it is affected by the presence of pilot fuel. First, suitable chemical kinetic schemes are selected based on experimental data collected from the literature. Then ID and LBV are estimated for different engine-like operating conditions. The effects of different proportions of hydrogen and methanol, as well as different lambdas, on ID and LBV in the high-pressure regime are considered. It is shown how both the ID of the pilot fuel and the LBV of the premixed fuel is strongly affected by the presence of either premixed fuel or pilot, respectively.