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Extensive use of internal combustion engines features the main disadvantage that their harmful emissions have an adverse impact on the environment. Thus, concentrations of the emitted pollutant emissions have been regulated in the past decade with the more stringent conditions that are enforcing the reduction of pollutant emissions. In recent times, combustion modelling employing computational fluid dynamics (CFD) in combination with experiment has become an irreplaceable tool in the design process of the diesel engines. Combustion process as a phenomenon of exceptional complexity can be numerically solved with detailed chemical kinetics or with the utilisation of approximated combustion models. An appropriate modelling approach to overcome the high computational demand is the Flamelet generated manifold (FGM) combustion modelling approach, which computes the chemistry kinetics in preprocessing and stores the result data in a look-up table that are used during the CFD simulations with interpolation procedure. Additional combustion models, that was employed in this work to simulate the combustion process in internal combustion engines is Three-zones extended coherent flame model (ECFM-3Z). The primary aim of the research is to analyse and validate numerical results of combustion process in a diesel engine obtained with FGM and ECFM-3Z approaches against experimental data. Numerical simulations are performed using commercial CFD software AVL FIRE™, where the calculated results such as mean in-cylinder pressure, mean temperature, rate of heat release, NO and soot emissions are calculated for single and multi- injection strategies. The NO emission trend observed in the experiment is well reproduced with both combustion models, while the computational time for CFD simulations with FGM is reduced approximately by half. The results obtained with both combustion modelling approaches are found to be in a good agreement with the experimental data. Thus, it is concluded, that both ECFM-3Z and FGM combustion modelling approaches are capable of predicting the combustion process in the real industrial diesel engines. |
