Numerical investigation of incompressible flow in grooved channels-heat transfer enhancement by self sustained oscillations

Gürer, Türker
In this study, forced convection cooling of package of 2-D parallel boards with heat generating chips is investigated. The main objective of this study is to determine the optimal board-to-board spacing to maintain the temperature of the components below the allowable temperature limit and maximize the rate of heat transfer from parallel heat generating boards cooled by forced convection under constant pressure drop across the package. Constant heat flux and constant wall temperature boundary conditions on the chips are applied for laminar and turbulent flows. Finite elements method is used to solve the governing continuity, momentum and energy equations. Ansys-Flotran computational fluid dynamics solver is utilized to obtain the numerical results. The solution approach and results are compared with the experimental, numerical and theoretical results in the literature. The results are presented for both the laminar and turbulent flows. Laminar flow results improve existing relations in the literature. It introduces the effect of chip spacing on the optimum board spacing and corresponding maximum heat transfer. Turbulent flow results are original in the sense that a complete solution of turbulent flow through the boards with discrete heat sources with constant temperature and constant heat flux boundary conditions are obtained for the first time. Moreover, optimization of board-to-board spacing and maximum heat transfer rate is introduced, including the effects of chip spacing.


Numerical and experimental investigation of forced filmwise condensation over bundle of tubes in the presence of noncondensable gases
Ramadan, Abdul-Ghani M; Yamalı, Cemil; Department of Mechanical Engineering (2006)
The problem of the forced film condensation heat transfer of pure steam and steam-air mixture flowing downward a tier of horizontal cylinders is investigated numerically and experimentally. Liquid and vapor-air mixture boundary layers were solved by an implicit finite difference scheme. The effects of the free stream non-condensable gas (air) concentration, free stream velocity (Reynolds number), cylinder diameter, temperature difference and angle of inclination on the condensation heat transfer are analyze...
Numerical simulation and analytical optimization of microchannel heat sinks
Türkakar, Göker; Okutucu Özyurt, Hanife Tuba; Department of Mechanical Engineering (2010)
This study has two main objectives: The performance evaluation of existing microchannel heat sinks using a CFD model, and the dimensional optimization of various heat sinks by minimizing the total thermal resistance. For the analyses, the geometric modeling is performed using the software GAMBIT while the thermal analysis is performed with FLUENT. The developed model compares very well with those available in the literature. Eight different metal-polymer microchannel heat sinks are analyzed using the model ...
Numerical investigation on cooling of small form factor computer cases
Orhan, Ömer Emre; Tarı, İlker; Department of Mechanical Engineering (2007)
In this study, cooling of small form factor computer is numerically investigated. The numerical model is analyzed using a commercial computational fluid dynamics software Icepak™ . The effects of grid selection, discretization schemes and turbulence models are discussed and presented. In addition, physical phenomena like recirculation and relaminarization are addressed briefly. For a comparison with the computational fluid dynamics results, an experiment is conducted and some temperature measurements are ob...
Analysis of single phase convective heat transfer in microchannels with variable thermal conductivity and variable viscosity
Gözükara, Arif Cem; Güvenç Yazıcıoğlu, Almıla; Department of Mechanical Engineering (2010)
In this study simultaneously developing single phase, laminar and incompressible flow in a micro gap between parallel plates is numerically analyzed by including the effect of variation in thermal conductivity and viscosity with temperature. Variable property solutions for continuity, momentum and energy equations are performed in a coupled manner, for air as a Newtonian fluid. In these analyses the rarefaction effect, which is important for the slip flow regime, is taken into account by imposing slip veloc...
Numerical analysis of natural convective heat transfer through porous medium
Aylangan, Benan; Yüncü, Hafit; Department of Mechanical Engineering (2006)
In this thesis, natural convective heat transfer through an impermeable and fluid saturated porous medium is investigated numerically. A FORTRAN based code is developed and used in order to present the outputs of the applied model and the assumptions. The solutions of flow fields and temperature fields are presented within the medium. Moreover, Nusselt number variations for different values of Darcy, Prandtl, and Rayleigh numbers, and some other thermodynamic properties are investigated and presented. Compa...
Citation Formats
T. Gürer, “Numerical investigation of incompressible flow in grooved channels-heat transfer enhancement by self sustained oscillations,” Ph.D. - Doctoral Program, Middle East Technical University, 2004.