Simulation Analysis on the Jet Flow Field of a Single Nozzle Spraying for a Large Ship Outer Panel Coating Robot

Abstract

A mathematical model of the cavity flow of the fan nozzle, a mathematical model of jet atomisation, and a simplified physical model of the equivalent entity are established. A simulation of the spraying flow at different spraying pressures is carried out using a 0.48 calibre nozzle as a case study, and compared with experimental data; error results between 4.3% and 7.5% indicate the simulation means used are reliable and the simulation model is valid. The simulation means include using the effective simulation model to further explore the evaluation index of atomisation characteristics; in the critical Weber number on the impact of atomised particles, analysis of the impact of the critical Weber number on the diameter of atomised particles and the speed of movement, and determining the critical Weber number; atomisation spraying effect, for atomisation pressure on atomised particle diameter, speed of movement, impact kinetic energy, deposition rate, and liquid film growth, etc. The results show that, in the existing high-pressure airless spraying equipment within the range of permissible pressure 6~16 MPa, with the increase in atomisation pressure, the better the atomisation effect of the paint, the better the atomised particle spraying adhesion deposition rate of the paint, and the better the overall spraying effect.