Simulation and validation of combustion characteristics of dual-fuel engines by developing advanced integrated 3D-CFD/chemical kinetics model

In the present study, the combustion process within OM-355 converted dual-fuel engine was investigated by the use of a coupled 3D-CFD/chemical kinetics framework. Methane and n-heptane were used as representatives of natural gas and diesel fuel in the simulations. The multi-dimensional KIVA-3V code, with modified combustion model, incorporated chemical kinetics mechanism for n-heptane and methane oxidation chemistry. Integration of chemical kinetics, as prominent outputs of combustion science, effectively enhanced predictions of KIVA’s combustion model. In doing so, CHEMKIN chemistry solver was integrated into KIVA code structure. Two different mechanisms of ERC V2 and Zheng & Yao’s mechanism were introduced and used in calculations. Simulation results showed that ERC V2 mechanism failed to predict mixing-controlled combustion correctly. However, Zheng & Yao’s mechanism was able to well-predict both chemically controlled and mixing-controlled combustion regimes. Although Zheng & Yao applied their reduced mechanism for low DI ratios in HCCI engines, results of present study shows that the mechanism is capable of modeling large DI ratios. Furthermore, developed model outputs were validated by available experimental data. Results revealed the fact that model is capable of accurate predictions for key combustion concepts like ignition delay, peak pressure magnitude and location and heat release rate where negligible discrepancy was observed comparing to experiments.

کلیدواژه ها:

Dual-fuel Engine ، Combustion ، KIVA ، CHEMKIN ، Combustion model