Parametric investigation on combustion and emissions characteristics of a dual fuel (natural gas port injection and diesel pilot injection) engine using 0-D SRM and 3D CFD approach

In the present study, combustion and emissions characteristics of a dual fuel engine has been investigated numerically. For numerical analysis, zero dimensional stochastic reactor model (0-D SRM) approach was used. SRM was validated with experimental results and used for parametric analysis of dual fuel engine by varying operating parameters such as premixing ratio of fuels, engine speed and exhaust gas recirculation (EGR) percentage. Numerically obtained results from 0-D SRM were found in good agreement with the experimental results. Combustion process in dual fuel engine has also been analysed using computational fluid dynamics (CFD) model using a commercial 3-D CFD engine simulation tool 'STAR-CD' in conjunction with mesh generator 'es-ice'. During engine combustion simulation with the STAR-CD code, PVM-MF (progress variable model - multi fuel) combustion model was used, which specially developed to characterize the multi fuel combustion. Spray evolution and combustion process has been analysed in a sector of engine cylinder to reduce the computational time during simulations. Numerically simulated data using this model was also found in good agreement with the experimental data. It was found that engine performance improved at higher engine load conditions and carbon mono oxide as well as unburned hydrocarbon emissions reduced. Effect of EGR on combustion and performance characteristics of dual fuel engine was also analysed.