Mathematical Modeling of Laminar and Turbulent Single-phase and Two-phase Flows in Straight and Helical Ducts

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dc.contributor.advisor Kevin M. Lyons, Committee Member en_US
dc.contributor.advisor Zhilin Li, Committee Member en_US
dc.contributor.advisor William L. Roberts, Committee Member en_US
dc.contributor.advisor K. P. Sandeep, Committee Member en_US
dc.contributor.advisor Andrey V. Kuznetsov, Committee Chair en_US
dc.contributor.author Cheng, Liping en_US
dc.date.accessioned 2010-04-02T18:58:39Z
dc.date.available 2010-04-02T18:58:39Z
dc.date.issued 2004-11-05 en_US
dc.identifier.other etd-10312004-071502 en_US
dc.identifier.uri http://www.lib.ncsu.edu/resolver/1840.16/4666
dc.description.abstract The purpose of this research is to investigate numerically the dynamics and heat transfer of laminar or turbulent flows in different media and complicated geometries, including the flow in a composite domain whose central portion is occupied by a clear fluid (turbulent flow) and whose peripheral portion is occupied by a fluid saturated porous medium (laminar flow); a laminar flow of a non-Newtonian fluid in a helical pipe; a laminar flow in a helical pipe filled with a fluid saturated porous medium; a two-phase laminar flow (non-Newtonian carrying fluid and solid particles) in a helical pipe. To model forced convection in a composite porous/fluid domain, the Brinkma-Forchheimer-extended Darcy equation is utilized for the porous region and a two-layer algebraic turbulence model is utilized for the flow in the central region. The effects of turbulence on velocity and temperature distributions as well as on the Nusselt number are analyzed. To investigate a fully developed laminar flow of a non-Newtonian fluid in a helical pipe, an orthogonal helical coordinate system is utilized and the Navier-Stokes and energy equations for the non-Newtonian fluid in this coordinate system are derived. The effects of the curvature and torsion of a helical pipe, the Dean number and Germano number on the velocities, secondary flow and heat transfer are presented. A full momentum equation for the flow in porous media that accounts for the Brinkman and Forchheimer extensions of the Darcy law as well as for the flow inertia is adopted to study the fully developed laminar flow in a helical pipe filled with a fluid saturated porous medium. The effects of the geometry of the helical pipe and the physical properties of the porous medium are investigated. Accounting for the flow inertia is shown to be important for predicting the secondary flow in a helical pipe. For 3D modeling of two-phase laminar flow in a helical pipe, the Eulerian approach is utilized for fluid flow and the Lagrangian approach is utilized for tracking particles. The interaction between the solid particles and the fluid that carries them is accounted for by a source term in the momentum equation for the fluid. The influence of inter-particle and particle-wall collisions is also taken into account. en_US
dc.rights I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. en_US
dc.subject non-Newtonian flow en_US
dc.subject orthogonal helical coordinate system en_US
dc.subject porous medium en_US
dc.subject helical pipe en_US
dc.subject force-coupling method en_US
dc.subject two-phase flow en_US
dc.title Mathematical Modeling of Laminar and Turbulent Single-phase and Two-phase Flows in Straight and Helical Ducts en_US
dc.degree.name PhD en_US
dc.degree.level dissertation en_US
dc.degree.discipline Mechanical Engineering en_US


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