Deising, Daniel (2019)
Modelling and Numerical Simulation of Species Transfer in Bubbly Flows using OpenFOAM.
Technische Universität Darmstadt
Dissertation, Erstveröffentlichung

Kurzbeschreibung (Abstract)

The aim of this work is the derivation of an improved closure model for the description of species transfer processes in two-phase gas-liquid flows which in the following, among others, can be used for the numerical simulation of bubble column reactors using a two-fluid model or also to obtain an improved design of fluid reactors. To gain detailed insight into the process, this research is focussed on the Direct Numerical Simulation (DNS) of species transport processes at single rising bubbles (and bubble groups) from the gas into the liquid phase. Due to the special suitability an algebraic Volume-of-Fluid (VoF) method based on the OpenFOAM interFoam solver is utilized. The species transfer is herein modelled employing a new single-field model named Continuous Species Transfer (CST) model which enables a detailed decription of the species transfer process in context of algebraic Volume-of-Fluid methods. A further novelty of the present work is that in contrast to common literature the influence of the bubble shape on the species transfer is considered as an additional influence variable. It is shown that the overall species transfer rate is effectively influenced by two separate mechanisms, leading to a more detailed description of species transfer processes: the generation of new interfacial area due to bubble deformation and the change of the concentration gradient at the bubble interface. The majority of this work is concerned with the comprehensive derivation, verification and validation of the presented numerical model. Modifications to the utilized flow solver are additionally presented and the improvements are quantified.

Frage zum Eintrag

Redaktionelle Details anzeigen