Mono-Disperse Spray Generation by a Flow Focusing Atomizer: A Numerical Study

Pneumatic flow focusing technology is a relatively new atomizing process first introduced in 1998. A liquid microjet is formed by a high speed co-flowing gas stream when a pressure drop is applied across an orifice. The microjet eventually disintegrates into fine droplets by the perturbing gas downstream of the atomizer exit. Under certain controlled flow regimes the resulting spray demonstrates strong monodispersity. In the present study, the gas flow is numerically modeled by a compressible turbulent flow solver and the liquid jet evolution is captured using Volume of Fluid (VOF) interface tracking method. Jet breakup parameters and drop size distribution are studied for different liquids and flow rates. Results are in good agreement with experiments and theoretical models.