INFLUENCE OF FUEL PROPERTIES ON THE DIESEL INJECTION PROCESS IN NONVAPORIZING CONDITIONS

International audience; This paper presents an experimental investigation of the influence of fuel density, viscosity, and surface tension on the diesel injection process (spray development and droplet size distribution) in non-vaporizing conditions. The spray development was captured in a pressurized vessel with a high-speed camera in order to obtain the penetration length and the spray angle. The droplet size distributions were measured by laser diffraction. A fuel matrix of eight fuels was designed including independent variations of fuel density, viscosity, and surface tension. Experimental conditions, such as injection pressure and air density, were varied according to current diesel engine conditions. The analysis focuses mainly on the quasi-stationary phase of the injection event. Results indicate that viscosity and to a lesser extent fuel density affect the spray characteristics. Increasing fuel density and viscosity by, respectively, 100 kg/m3 and 6.5 mm2/s induces longer spray tip penetration (up to 7%) with a narrower spray angle (drop of up to 3 deg) in quasi-stationary conditions. An increase in the Sauter mean diameter (up to 23% or 3 µm) was also observed. An increase in surface tension from 18 to 30 mN/m did not induce any significant modifications in the droplet size or in the spray development. Correlations, some of which are based on existing ones, are proposed to estimate the spray cone angle, the spray tip penetration, the SMD (Sauter mean diameter) and the drop size distribution considering the experimental conditions and the fuel properties.