Experimental Study on Macro Characteristics of High-Pressure Diesel Spray-Wall Impingement Behaviors 2019-01-5079

The spray-wall interaction is a common phenomenon in modern diesel engine that has an important influence on the combustion and performance of the diesel engine. The main focus of this paper is to analyze the macro characteristics of diesel spray impingement with the experimental data and thus support simulation research. This paper studies the surface temperature range from 300°C to 500°C and 20°C is studied as comparison. Injection pressures range from 70 MPa to 110 MPa, and based on the obtained data, several aspects are analyzed. The results show that the distribution of the fuel concentration is quite inhomogeneous after the impingement with a cold wall (20°C) which causes a large number of dense droplets occupying most of the internal space with the concentration more than 60%. While the thin spray only occupies the external space partially. According to the experimental data, increasing the injection pressure contributes to improving the mixing process. The experimental results with different surface temperatures of the wall show that higher surface temperature has a significant influence on the evaporation of the fuel and fuel-air mixture. Furthermore, a higher surface temperature is a benefit to the distribution of fuel.