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This paper presents a detailed sensitivity analysis of the sparse-Lagrangian multiple mapping conditioning (MMC) model to different parameters in simulations of n-dodecane flame A which is adopted by the engine combustion network (ECN). The model is fully coupled with a large eddy simulation (LES) approach. A gas-jet model is used for the fuel injection. The MMC-LES model is first examined for a non-reacting case and the sensitivity of the results to variations in the inlet turbulence intensity are examined. It is found that the mixture fraction profiles agree well with the experimental data. The vapour penetration is overpredicted but there is significant improvement by increasing the turbulence intensity of the inlet jet from 10% to 15%. The model sensitivities to inlet turbulence intensity, mixing model parameters and chemical kinetics is then investigated for reacting cases. Simulations are performed at various levels of ambient oxygen (13% - 21%).

This experimental study examines the effect on performance and emission outputs of a compression ignition engine operating on biodiesels of varying carbon chain length and the degree of unsaturation. A well-instrumented, heavy-duty, multi-cylinder, common-rail, turbo-charged diesel engine was used to ensure that the results contribute in a realistic way to the ongoing debate about the impact of biofuels. Comparative measurements are reported for engine performance as well as the emissions of NOx, particle number and size distribution, and the concentration of the reactive oxygen species (which provide a measure of the toxicity of emitted particles). It is shown that the biodiesels used in this study produce lower mean effective pressure, somewhat proportionally with their lower calorific values; however, the molecular structure has been shown to have little impact on the performance of the engine.