Experimental analysis of spray behavior and lubrication performance under twin-fluid atomization

The spray behavior of a twin-fluid nozzle (TFN) can seriously affect lubrication performance, cutting fluid consumption and tool life during the manufacturing process. It is important to study the spray behavior and droplet size distribution characteristics of twin-fluid atomization to improve machining performance and reduce environmental pollution. In the current study, first, via a phase Doppler method, the spatial distribution of spray behavior of a TFN with and without a self-excited vibrating cavity (SVC) is analyzed and compared. Then, under various gas-to-liquid mass ratio values, the counts percent and cumulative distributions of droplets of a TFN with different SVC structures are further investigated. In addition, comparative investigations of the effects of different TFNs on the lubrication performance are conducted. The results show that the SVC structural parameter and gas-to-liquid mass ratio have an important influence on the secondary atomization of a TFN with an SVC, which significantly affects the spray behavior and droplet size distribution characteristics. The velocity differences between the gas-liquid two phases and the strong turbulence around the SVC are the key factors affecting the secondary atomization. The SVC can significantly increase the spatial coverage of droplets and improve the droplet spatial distribution characteristics of diameter and number concentration. The TFN with an improved SVC has better spray behavior and droplet size distribution characteristics, resulting in reductions in tool wear, cutting temperature and surface roughness of approximately 24.84 %, 21.24 % and 31.86 %, respectively, compared with the TFN without an SVC.