الفهرس 
Abstract
Plan of StudyOnly 14 pages are availabe for public view
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Abstract
Introduction: Conjugate heat transfer, which is the ultimate goal in this work, is a coupled problem involving heat transfer in a fluid domain (convection) as well as in the surrounding solid wall (conduction). Heat transfer by conduction and convection simultaneously occurs in the majority of engineering applications, such as heat exchangers and fins. Efficiently combining heat transfer in solids and fluids is the key to design effective coolers, heaters, or heat exchangers. Modeling and designing of such heat transfer devices are complicated due to coupling, which involves a rather large number of parameters describing both fluid and solid domains. The research problem: Modeling conjugate heat transfer to get a simple accurate solution for the problem by using the Compact Thermal Model (CTM). Then, the research aims to: Studying the conjugate heat transfer. An intelligent strategy is used in this study, which decouples the problem by modeling each domain alone, followed by merging models of both domains using continuity conditions at the solid/fluid interface. Compact thermal model solution was obtained for the convective heat transfer problem to get a more general simple expression for any boundary conditions (heat flux density and temperature profiles). This solution offers many advantages over the simple approach using Heat Transfer Coefficient (HTC) (i.e. any space distribution, not just uniform). Steps of study: Chapter 1 gives an introduction to the conjugate heat transfer. Chapter 2 considers the problem formulation, dimensional analysis and analytic solution of convection and conduction problems for general boundary and inlet conditions. Chapter 3 discusses the numerical solution for the convection problem, solver selection and mesh dependency study. Chapter 4 presents and discusses the results from the analytic convection solution, constructing the CTM and solving the conjugate problem. Chapter 5 shows the conclusions and the recommended future work. The study concludes: An analytical solution for the laminar forced convection heat transfer problem in a straight circular pipe has been derived for arbitrary thermal boundary and inlet conditions under mild assumptions that were proved to have quite negligible effect by comparison with the numerical solution. The solution was used to derive a simplified CTM, which is extremely more accurate than the classical heat transfer coefficient model, at the expense of a mild complication of problem formulation. Application of the CTM for convection has been extended to cover: Straight ducts with circular cross section area, fully developed velocity profile at the duct inlet and various inlet and wall thermal conditions. The Compact Thermal Model gently treated the conjugate heat transfer by introducing a seamless merger of CTMs developed for solid domain and fluid domain independently. On the other hand, the HTC cannot treat conjugate heat transfer problems as we do not know which q or T profiles are present at the interface and it would not be possible to have many HTC correlations for any combination of fluid-solid domains.