In the introductory part of this Master’s thesis we present the use of Taylor flow in the area of microfluidics, which offers many advantages in comparison to other flow regimes, mostly due to its high coefficient of mass transport and heat transfer. It is also a very efficient flow regime for carrying out chemical reactions due to its high interfacial surface area.
With the recent increase of computing power, mathematical modelling of microfluidics processes is becoming a crucial part of designing microfluidic reaction systems, because microfluidics systems are often expensive and complex to set up, and parameters within the system can be difficult to regulate post initial setup. With the use of numerical tools, we are able to deduce the efficacy of microchannel geometry, operating parameters and other variables much faster, easier and at a lower cost.
In this thesis we researched the effect of different microchannel geometries on the formulation of Taylor flow in a two-phase liquid-liquid system. The generated flow regimes were simulated numerically with the level-set and finite element methods. The results gave an insight into optimal parameters for the given phase velocities and also helped evaluate the effect of different microchannel geometries on the flow regime.
The most promising microchannels for generating Taylor flow were microchannels with long and narrow main channels. Microchannels with shorter and wider main channels generally yielded poorer results, as they often failed to produce segmented flow and produced parallel flow instead. We also tested the implementation of separation pillars, which were intended to produce droplet flow. The pillars resulted in a minor improvement in most cases, but due to their simplicity remain a suitable addition to the microchannel geometry.
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