Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.556100
Title: CFD simulation of annular flows through bends
Author: Tkaczyk, Piotr
Awarding Body: University of Nottingham
Current Institution: University of Nottingham
Date of Award: 2011
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Abstract:
There is particular interest in the oil industry, in gas/liquid distribution in pipe line systems. The presence of bends has a significant effect on gas/liquid flows. Bends are often necessary to fit the equipment into limited spaces e.g. in plants or on oil rig platforms. As part of designing industrial systems, it is therefore important to be able to understand how liquid and gas move around bends. The aim of this research is to develop a method for predicting gas/liquid annular flows. A 3D CFD-based method is therefore developed to solve for annular flows in pipes and is applied to a range of pipe bends. In the presented study, the two-phases are gas and liquid. Multiphase fields can be handled as a continuum gas field, continuum liquid filed and as liquid droplets of varied diameters. The liquid travels along the walls as a film and in the gas core in the form of droplets. The presented approach accounts for the dynamics of the droplets flow in the gas core and their interaction between them. The liquid film is solved explicitly by means of a modified Volume of Fluid (VOF) method. The droplets are traced using a Lagrangian technique. The film to droplets (entrainment) and droplets to film (splashing, spread, bounce and stick) interactions are taken into account using sub- models to complement the VOF model. In free surface flows, a high velocity gradient at the gas/liquid interface results in high turbulence generation. In order to improve the momentum transfer between the phases at the interface, a correction to VOF is also implemented based on the work of Egorov [1]. A detailed comparison between the model and experimental data for vertical, Wolf et al. [2], and horizontal annular flows, Butterworth and Pulling [3], show reasonable agreement. The model is then applied to annular flow in bends, Maddock et al. [4], Anderson and Hills [5], Sakamoto et al. [6]. The comparison between the model and experimental data found in the literature show a good agreement. The model is also successfully applied to medium size (127mm) pipe configurations run at Nottingham University as part of a parent project. The model is finally applied to large pipe diameters encountered in industrial oil/gas applications to investigate scale issues and the model potential in industry.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: L
EThOS ID: uk.bl.ethos.556100  DOI: Not available
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