A study of the flow and atomization characteristics of impinged diesel spray on a chamber wall

Abstract

The purpose of this study was to investigate the flow and atomization characteristics of an impinged spray on the wall of a chamber with a high-speed diesel spray injected from a common-rail system under various experimental conditions. The flow characteristics of the impinged spray were visualized and the droplet velocity distributions were obtained using a particle image velocimetry (PIV) system. The atomization characteristics of an impinged spray on the wall were investigated in terms of mean droplet size and radial mean velocity at various injection and wall parameters such as injection pressure, ambient pressure, the nozzle-wall distance, and the inclined angle of the wall. Additionally, the velocity distributions from the PIV system were compared with the measured results of the phase Doppler particle analyzer (PDPA) system. It is revealed that the radial spray penetration and the flow field on the impinged wall increase with the increase of the injection pressure and inclined angle of the wall. Comparison results of radial velocity on the impinged spray between PIV and PDPA show that the maximum value of radial velocity is similar. The distributions of SMDs under various experimental conditions show that atomization characteristics are affected by high-momentum droplets. The increases of injection pressure and nozzle-wall distance cause the decrease of droplet diameter, and measured droplet diameters are mostly under 25 mu m.