Numerical and experimental investigation of direct injection fuel spray characteristics

A liquid sheet model for the prediction of the development of a hollow-cone spray emerging from a pressure-swirl atomiser into quiescent air is examined in the present paper. The model consists of a sheet atomisation model and a model for the subsequent spray development. The sheet atomisation process is modelled by introducing fuel "blobs" of size equal to the sheet thickness at a distance equal to the breakup length of the liquid sheet away from the injector, while the subsequent breakup of the blobs is modelled using the Reitz-Diwakar model. The model is implemented within the STAR-CD code. In addition, experimental results were obtained using laser-diffraction and phase-Doppler particle analysis for droplet size measurements, while for the determination of macroscopic spray structure a high-speed rotating drum camera and an Oxford Lasers copper-vapour laser were utilised. The numerical results are compared against experimental data in the form of spray tip penetration and temporal development of arithmetic mean droplet diameter, as well as radial distribution of Sauter mean diameter. The numerical model predicts the early spray tip velocity accurately and the droplet sizes with acceptable deviation.