Numerical simulation of monodisperse droplet generation in pneumatic extension nozzles

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The aim of this research project is the development and analysis of robust, accurate and efficient simulation techniques and the realization of special CFD tools for nonstationary multiphase flow problems so that the generation of monodisperse droplets from one or several laminar liquid disperse phases via pneumatic extension nozzles can be treated. We concentrated in the first period onto the realization and validation of efficient numerical components in the Open-Source CFD package FEATFLOW to simulate and control - via modulation - the generation of droplets with prescribed uniform size and separation length for given geometry details regarding capillary size and nozzle shape. Moreover, we extended the flow solver to handle nonlinear fluids with shear-dependent viscosity, mostly based on models from Cross, Carreau and Power Law-type, in which case the disperse phase shows a different multiphase behaviour, particularly in the case of dripping which is our preferred mode. In the next period, we will bring together our so far developed methods and software tools for monodisperse droplets, non-newtonian fluids and modulation approaches to handle micro-encapsulation with liquid cores/compound liquid jets (or alternatively solid particles as cores) in which case the fluid is allowed to be non-newtonian.