Toward Realistic Dual-Fuel Engines Simulation Using Chemical Kinetics in Multi-dimensional CFD

Toward Realistic Dual-Fuel Engines Simulation Using Chemical Kinetics in Multi-dimensional CFD

Dual-fuel compression ignition engines seem to be an inexpensive alternative to conventional diesel engine. Drastically reduction of fuel consumption and applicable performance characteristics has led these engines to be an achievable technology for future power generation units. However, accurate simulations of the dual-fuel combustion require utilization of detailed chemistry combined with a fluid flow simulation as Computational Fluid Dynamics (CFD) workstation. A multi-dimensional CFD modeling was conducted for a direct injected dual-fuel engine computations based on KIVA 3V code. CHEMKIN chemistry solver was also integrated into code structure of KIVA so that parameters regarding to combustion were calculated by introduced chemical kinetics mechanism to establish advanced combustion model. As combustion in dual-fuel engine proceeds both in chemically-controlled and mixing-controlled modes, a hybrid combustion model was developed to enable realistic combustion predictions. In doing so, combustion of the premixed charges of fuel and oxidizer where chemistry effects are dominant was modeled by Perfectly Stirred Reactor (PSR) model and diffusion high-temperature combustion was modeled by Eddy Break-Up model. Temperature threshold of 1000 K was used as shifting parameter between two combustion modes. Simulation results of in-cylinder pressure, heat release rate and emissions showed acceptable agreement compared to experimental data.