Development of a Physically/Chemically Based Approach for 2-Stage Ignition Delay Calculation in Medium Speed Dual-Fuel Engines

A New Combustion Model for Medium Speed Dual-Fuel Engines in the Course of 0D/1D Simulation

“…The ignition delay model was presented in detail in Ref. [22] and is, therefore, only briefly described in the following. The spray model used to simulate the spray behavior of the pilot injection is the 1D transient spray model from Musculus and Kattke, which is described in detail in Ref.…”

“…Furthermore, an explicit solution for the mixing temperature of the fully evaporated part of the fuel was developed [22]. With this mixing temperature a temperature distribution inside the spray is calculated at every timestep.…”

“…To calculate the ignition of the pilot fuel, an ignition delay model is developed in Ref. [22] based on homogeneous reactor calculations using the open-source software Cantera [24]. The extended n-heptane mechanism from the Lawrence Livermore National Laboratories [25] is used with n-heptane as reference for the pilot fuel and methane as reference for the natural gas.…”

“…The reaction progress c is coupled to the mass of the pilot fuel 𝑚𝑚 𝐷𝐷 and the respective mass flow 𝑚𝑚̇𝐷𝐷. The term Δ𝑐𝑐 𝑖𝑖,𝑗𝑗,𝑆𝑆𝑟𝑟𝑆𝑆𝑐𝑐 accounts for the chemical reactions inside the control volume by integrating the inverse of the ignition delay time over the timestep at the position of the most reactive mixture inside the control volume [22]. To account for wall contact of the spray, the reaction term is set to zero for all control volumes that are located outside the combustion chamber.…”

“…In a previous work of the authors, an ignition delay model for medium speed dualfuel engines was presented [22]. The model combines a 1D spray model with a mixingcontrolled evaporation model and an approach for 2-stage autoignition, including the low temperature heat release.…”