Abstract
A liquid or a suspension is divided into small droplets by atomization. The mean goal is either the equal distribution of the droplets, or the generation of large surface areas of the liquid phase in order to increase heat- and mass-transfer. In two-phase atomization the spatial and time distribution of the mean droplet diameter of the spray depend on the total pressure upstream of the nozzle, the volumetric flow rate of the liquid and the gas, as well as on the flow regime in the nozzle. Thus the radial and axial profile of the void fraction inside the nozzle are measured with an electrical measurement technique. In addition, the flow in the nozzle is visualized by a high-speed camera. Three flow regimes are identified. These are bubbly flow, plug flow, and annular flow.
At the smallest cross section of the nozzle critical mass flow is observed. A literature review on models to calculate the critical mass flow is given. The calculated and the measured mass flow rates are compared.
