Original scientific paper

DIESEL AND BIODIESEL MACRO-SPRAY CHARACTERISTICS

Primož Pogorevc
Breda Kegl
Želimir Dobovišek

Abstract

Abstract
Characteristics of fuel injection and spray formation in the engine combustion chamber are most important factor of up-to-date diesel engines, influencing their effective performance parameters and exhaust emissions. During last few decades alternative automotive fuels, such as biodiesel have received salient attention. Even though it has similar physical properties as diesel fuel, higher density, viscosity and surface tension of biodiesel may have a dominant influence on the spray formation and sometimes cause spray anomalies - such as contact between fuel and combustion chamber, poor mixing with air (bigger fuel droplets) etc.
Results of the investigation about the impact of the diesel and biodiesel fuel physical properties on the injection and spray characteristics are presented in the paper. Physical properties of both have been examined and used in the mathematical model of the conventional injection system. The model was derived in IEPO - Institute for Power, Process and Environmental Engineering Faculty of mechanical engineering, University Maribor, simulation code Bkin, and was verified by experiment carried out on the fuel injection system test bench and on the engine. In a special test chamber the macro-characteristics of the spray injected into motionless air at the atmospheric pressure and room temperature (spray penetration distance, angle, and spray shape) have been measured and spray images were recorded by the high-speed camera (2500 frames/s). Using 3D simulation program (AVL "Fire") and including for the purpose of these investigations a few new estimates, the injection process for both fuels have been simulated and compared with the results obtained by experiments. These results are presented and discussed in the paper.

Keywords

biodiesel fuel atomization and fuel injection by pressure; material model investigation viewpoint; mathematical model investigation viewpoint; flow through nozzles; flow of two phase fluids; diesel fuel; biodiesel fuel

Hrčak ID:

9289

URI

https://hrcak.srce.hr/9289

Publication date:

9.3.2007.

Article data in other languages: croatian

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