Spray characterization of bell-cup atomizer comparing with powder spray gun

T. Soma, S. Amemiya, T. Katayama, Y. Saito, Y. Matsushita, H. Aoki, R. Sakabe, T. Inamura, M. Daikoku, J. Fukuno

Research output: Contribution to conferencePaperpeer-review


The motions of particles injected from two different sprayers were investigated. The present investigation deals with automotive paint sprayers, high-speed rotary bell-cup atomizer and powder spray gun. The liquid droplets and powders in each paint system were modeled as undeformable spherical particles, and the two-phase flow was numerically computed with the Euler-Lagrange approach. The Reynolds-averaged Navier-Stokes equation was solved with the standard k-ε model. The effect of turbulent eddies on the droplet motion was estimated using a stochastic approach. Electrostatic force for particles was defined as gradient of the electrostatic potential calculated from the Poisson’s equation. As a result, the particles were ejected from bell-cup atomizer parallel to target, and then were curved in a vertical direction by shaping air flow blown from rear of the bell-cup. In case of powder spray gun, the particles were injected toward the target, and spread by colliding with deflector. Despite the difference in spray system, the spread of spray near nozzle was observed in both sprayers. Some particles in ghost were entrained by high-speed airflow and reached the target, and some propagated radially outward and missed the target. The spray spread with the mean particle diameter due to the inertia. Meanwhile, around the central axis, the spray mass density of bell-cup atomizer was lower than that of powder spray gun in transport field. This occurs because swirl flow was generated by shear force due to rotation of bell-cup. The coating film on the target had a relatively strong tendency to be torus-shape compared with powder spray gun.

Original languageEnglish
Publication statusPublished - 2015
Event13th International Conference on Liquid Atomization and Spray Systems, ICLASS 2015 - Tainan, Taiwan, Province of China
Duration: 2015 Aug 232015 Aug 27


Conference13th International Conference on Liquid Atomization and Spray Systems, ICLASS 2015
Country/TerritoryTaiwan, Province of China


  • Bell-cup atomizer
  • Euler-Lagrange approach
  • Numerical simulation
  • Powder spray gun


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