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Numerical Modeling of Two Phase Slug Flow in Horizontal and Slop Variation Pipes

Bohluly, Asghar | 2014

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 45779 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engeeniring
  6. Advisor(s): Borghei, Mahmood; Saidi, Mohammad Hasan
  7. Abstract:
  8. Designers consider formation of slug flow in pressurized pipes because of hazardous effects of this flow pattern. Therefore, researchers, using different methods, attempt to study formation of slug flow and its effects. For numerical simulation of this phenomenon, In spite of existence of commercial 2D or 3D two-phase models, numerical models used for the slug flow modeling are 1D. In this thesis, a 2D model has been developed to simulate the initiation and formation of slug flow and estimation of the effects in pressurized pipes. Most important assumptions used in this model are existence of turbulence, surface tension and air compressibility. Isothermal condition has been supposed for compressibility modeling. Youngs VOF method, that improved by FGVT schema, is used in the model for interface capturing. A second order coupled method between interface tracking and hydrodynamic model has been implemented for computation of momentum advection. Simulation of pipe slope variation has been considered in the study that is an important factor for changing of flow pattern in prevailing conditions, so an artificial slope change method proposed and has been implemented. For verification and validation of accuracy of developed model, numerous test cases in various conditions have been simulated by the model and have been compared with experimental, analytical or other numerical researcher’s results.
    Experimental tests with similar conditions of numerical model have been studied for verification of the model in simulation of slug flow conditions. Pressure fluctuations in laboratory conditions analyzed by spectral methods and have been compared with numerical model results. Furthermore, generation of slug flow has been studied under different conditions including the lack of turbulence model or other effective factors for sensitive analysis.
  9. Keywords:
  10. Numerical Simulation ; Two Phase Flow ; Slug Flow ; Compressibility ; Artificial Slope Variation

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