Experimental and numerical analysis of the internal flow of a rotary atomizer

Using high-speed imaging technique and the volume of fluid (VOF) method, an experimental and numerical analysis of the flow behavior inside a rotary atomizer was conducted. To scrutinize the effect of gravity on the internal flow of the nozzle, the experiments and CFD simulations were carried out at horizontal (without gravity effect) and vertical (with gravity effect) configurations. The mass flow rate exiting the nozzle orifices was measured; the flow behavior inside the nozzle orifices was investigated; the thickness of the rivulet and film inside the nozzle orifices was compared to existing analytic models. It was found that gravity had a significant impact on the flow distribution inside the nozzle cavity. The liquid flow distribution exiting the nozzle orifices was not uniform in the vertical configuration (due to gravity). Four wave patterns were identified on the surface of the nozzle disk: smooth film, concentric wave, spiral wave, and arc-shaped wave.