Influence of atomizing core on droplet dynamic behavior and machining characteristics under synergistically enhanced twin-fluid spray

The droplet dynamic behavior of spraying during the manufacturing process affects tool life, cooling, and lubrication. A detailed understanding of droplet dynamic behavior is required to improve the surface quality while reducing the cutting fluid consumption. In this study, quantitative measurements for droplet diameter, number concentration, and axial velocity were carried out through a phase Doppler particle analyzer technique. The droplet characteristic spatial distributions of a standard twin-fluid nozzle (STN) and a novel twin-fluid nozzle (NTN) under different gas-to-liquid mass ratio (GLR) values were analyzed in detail. The results showed that the high-speed internal gas flow of an atomizing core has a significant effect on improving the synergistically enhanced atomization behavior, and more smaller droplets and an increased droplet momentum are easily obtained. Furthermore, a better spatial distribution of atomization characteristics can be achieved under a higher GLR of 4.3%. Furthermore, the effects of the novel atomizing core structural parameters on the droplet mean velocity spatial distribution, droplet turbulence, and root mean square velocity fluctuation were investigated. The results also showed that the improved NTN can effectively improve the spray atomization performance and droplet dynamic characteristics. In addition, comparative studies of the effect of the atomizing core structure on the machining performance were performed. Compared with the STN, the improved NTN achieves a significant reduction in cutting temperature, tool wear, and surface roughness of 17.25%, 33.96%, and 37.83%, respectively, owing to the better droplet dynamic characteristics and spatial distribution of spray atomization characteristics.