Abstract
In this paper, the influence of surface roughness of the nozzle on the characteristics of atomized droplets in an MQL system is studied using a computational fluid dynamics (CFD) simulation. The study was carried out by first creating a 3-D model of the nozzle using Creo3.0 which was then imported by using the Ansys Fluent software where various parameters such as solver and materials were defined to enable the study of the characteristics of the atomized droplets which were to be formed. The input simulation parameters specified were air pressure inlet, mass flow inlet and pressure outlet. Nine simulation runs were carried out for surface roughness at the range of 1.5-16.8 mu m and pressure of 0.275-0.55 MPa. The simulation results showed that under the same pressure and mass flow conditions, the surface roughness of the nozzle will have some influence on the characteristics of the droplet. As the surface roughness of the nozzle increases, smaller droplet diameter will be obtained. Under pressure of 0.55 MPa, and the nozzle with 16.8 mu m roughness minimum average droplet size of 5.705x10(-6) m can be produced. ANOVA performed revealed that both surface roughness and pressure are significant in affecting the droplets formed.