The numerical simulation of biofuels spray

In this paper, the possibility of replacing mineral diesel fuels with different biofuels is analyzed. The study focuses on a numerical investigation of biofuels' influence on an injected fuel-spray cone's angle and length, which have further influence on the combustion process and the formation of pollutants in internal combustion engines. The influence of different physical and chemical properties of pure mineral diesel fuel, biodiesel fuel and their blends on spray characteristics was investigated with the AVL FIRE simulation program. Several different empirical model parameters, usually the engine-operating regime and biofuel used, must be defined when using numerical models. In this study, the numerical model implemented in AVL FIRE was modified so that all model parameters were determined regarding biofuel properties and engine-operating conditions. Experimental measurements of spray development in a cylindrical chamber pressurized with nitrogen at 40-60 bar were performed for validation of the modified numerical model. Photos of spray development were taken with a high speed camera simultaneously with pressure and needle-lift signals. The comparison of experimental and numerical results confirmed the usability of the numerical model. Numerical results of spray development for different biofuels under different operating regimes and ambient pressure confirm the possible usage of biofuels as a replacement for mineral diesel fuel in diesel engines with the early generation of fuel injection systems. (c) 2014 Elsevier Ltd. All rights reserved.