Evaluation of Turbulence Models in Gas Dispersion
MetadataVis full innførsel
Several earlier model validation studies for predicting gas dispersion scenarios have been conducted for the three RANS two-equation eddy viscosity turbulence models, the standard k-ε (SKE), Re- Normalisation group k-ε (RNG) and Realizable k-ε (Realizable). However, these studies have mainly validated one or two of the models, and have mostly used one simulation case as a basis for determining which model is the best suited for predicting such scenarios. In addition, the studies have shown conflicting results as to which model is ideal for dispersion simulations. The aim of the study was therefore to assess three well-known RANS two-equation eddy viscosity models, in four different gas dispersion cases. The purpose was to evaluate the models' behaviour compared to experimental data, in order to see which of the models was best suited for predicting dispersion scenarios. The cases used in the thesis were: CO2 dispersion in a cross- wind, neutral dispersion in an urban environment, hydrogen jet impinging on a surface, and a dense jet dispersion on an industrial site. All simulations were conducted with a CFD software that partially resolved the geometry, and was designed for large complex multiscale flow scenarios. The most important parameters for assessing the turbulence models were accuracy of the simulation results and computational time used. Overall, SKE seemed to be the best-suited model for 3 out of 4 cases, and provided good results for all the scenarios. However, RNG also provided reasonably results in all cases, in a practical timeframe. Realizable was the model that commonly used longest computational time, and was found least suitable for 3 out of 4 cases.
UtgiverThe University of Bergen
OpphavsrettCopyright the Author. All rights reserved
Viser innførsler beslektet ved tittel, forfatter og emneord.
Ledsaak, Karina (Master thesis, 2016-11-20)Hydrocarbon reservoirs exhibiting features inherited from former karst processes acting on the reservoir rocks are relatively common worldwide. However, on the Norwegian continental shelf, paleokarst plays have only recently ...
3D stochastic modelling of fault zones in siliciclastic reservoirs. Implications for reservoir description and fluid flow modelling Fachri, Muhammad (Doctoral thesis, 2014-12-16)Fault zones in siliciclastic rocks form distinct volumetric entities and typically exhibit great structural complexity. While it has been considered that the main impact of fault zones to fluid flow is to baffle or block ...
Andersen, Christine Torsvik (Master thesis, 2014-11-18)The effects of overburden, burial depth, source-receiver distance and frequency on seismic resolution have been studied in this thesis. Synthetic seismic sections of two plaster models, where a volume of plaster has been ...