Drop model for continuous milli‐beads production. Issue 4 (11th April 2017) - Stelian, Carmen
Abstract : The production of solid spheres from droplet solidification is of great interest, but needs a careful control of the drop diameter. An improved formula predicting the volume of the released droplets has been derived by reconsidering the approximate balance relating the gravitational and surface tension forces proposed by Tate. The simple proposed model can easily be used for the design of experiments in which liquid droplets should be produced, as for example, surface tension measurements or milli‐beads production. Abstract : Production of solid spheres from droplet solidification is gaining more and more interest, but needs a careful control of the drop diameter. The technique of dropping liquid alumina from a nozzle is used for processing the starting materials which are filling the crucibles in sapphire crystal growth technology. In the present work, experimental, theoretical and numerical analysis is carried out in order to describe the time evolution of the drop formation from a capillary tube. The main goal of this study is to develop a physical model able to explain the dynamics of drop formation, with application in drop weight method and production of small alumina balls. A new formula predicting the volume of falling drops is derived from the force balance at the instant of drop detachment. The theoretical predictions are compared to present numerical computations and experimental results of alumina milli‐beads production. Based on this model, the crucible and capillary tube geometries and the process parameters can be designed in order to get continuous production of reproducible droplets for mass production.