Development of a technology to produce monodispersed microparticles based on the formation of drops from viscous non-Newtonian liquids sprayed through a fan jet nozzle

Abstract

A new technique has been developed to produce microparticles as small as 30 μm from a non-Newtonian viscous fluid such as sodium alginate. A fan jet nozzle was employed to produce a laminar jet, which was unstabilized by a rapid air gas stream co-axial to the flow. Behavior studies were conducted to show the performance of the system under the variation of parameters like air and liquid flow (imposed by pressure), and also viscosity, and their influence of the generated particles. Also, the downstream jet flow was parameterized as a function of controlled external variables: air and liquid pressure and viscosity. Agreement was found between the model and experimental data. Microbeads were obtained at different conditions to obtain a mathematical relationship between size parameters (Sauter Mean Diameter) and forces acting in the system, represented as dimensionless numbers: liquid/air mass ratio and Weber (We) and Ohneshorge (Oh) numbers. Based in wave propagation mechanisms, three semi-empirical models have been proposed based in these dimensionless numbers. Further experimental data agrees accurately with the models, and allow the prediction of the microbeads size obtained by this technique.