A study on an application of a hybrid break-up model for dimethyl ether atomization in a common-rail injection system

In this study, experimental and numerical investigations were performed to analyse the spray characteristics of dimethyl ether (DME) fuel in a common-rail fuel injection system. In order to analyse the DME fuel spray, overall spray characteristics such as the spray tip penetration, the spray evolution process, and the droplet size distribution were investigated by an application of the hybrid break-up model combined with primary and secondary break-up phenomena. The spray development process and spray tip penetration were measured experimentally from injected DME spray images obtained using a visualization system, while the microscopic characteristics were experimentally measured by a phase Doppler particle analyser system. Calculations based on hybrid break-up models were validated against the experimental results, and the associated break-up constants were optimized after the validation. Based on the optimized break-up constant, the calculated results under various experimental conditions were compared with measured results such as the spray development, the spray tip penetration, the Sauter mean diameter (SMD), and the SMD distribution.