Improving flow structure and natural convection within fin spacings of plate fin heat sinks

Download
2015
Özet, Mehmet Erdem
The main objectives of this thesis are to numerically investigate the previously observed recirculation zones and longitudinal vortices that occur in low fin height plate finned horizontal heat sinks and to improve the flow structures and heat transfer in these zones using various approaches with the help of simulations performed using commercially available CFD software. The approaches used for improvements are replacing the outer most fins with higher ones, introducing gaps on the length of the fins in various patterns, and introducing interstitial fins of different shapes within the channels among the plate fins. Starting with a validated model of the original low height plate fin heat sink and making the geometric modifications without altering the solution strategy, newer models that do not require experimental validation are obtained. The original model and the newer models are used in a series of simulations with related parametric analyses. The performances of the newly introduced heat sink geometries are compared with the performance of the original low height plate fin heat sink using the simulation results. Among these alternatives the one performing the best is selected as an optimal solution to the recirculating flow problem observed in the low height plate fins.

Suggestions

Numerical and experimental analysis for comparison of square, cylindrical and plate fin arrays in external flow
İnci, Aykut Barış; Bayer, Özgür; Department of Mechanical Engineering (2018)
Geometrical optimization of square, cylindrical and plate fins for heat transfer augmentation is numerically performed in the external flow. Heat transfer performance of fins with different profiles are compared with same Reynolds number. The relation between the thermal characteristic of fins and boundary conditions like free-stream velocity and heat input are investigated. Experimental studies are performed using manufacturable fins to validate numerical model. Heat transfer correlations are derived in or...
Design and analysis of a vertical axis water turbine for river applications using computational fluid dynamics
Demircan, Eren; Aksel, Mehmet Haluk; Pınarcıoğlu, Mehmet Melih; Department of Mechanical Engineering (2014)
The main purpose of this study is to design a Darrieus rotor type vertical axis water turbine using Computational Fluid Dynamics (CFD) in order to be used in river currents. The CFD modeling is based on two dimensional numerical solution of the rotor motion using commercial Unsteady Reynolds Averaged Navier-Stokes solvers, Ansys Fluent and CFX. To validate the two dimensional numerical solution, an experimental Darrieus rotor type water turbine from literature is studied and performance of several turbulenc...
3-D numerical simulations of fluid flow and heat transfer in various micro conduits
Turgay, Metin Bilgehan; Güvenç Yazıcıoğlu, Almıla; Department of Mechanical Engineering (2017)
In this work, it is aimed to investigate the effect of roughness geometrical properties and configurations on laminar flow and heat transfer characteristics in microchannels, numerically. For this purpose, two-dimensional parallel plate, and three-dimensional trapezoidal microchannels with different roughness properties are modeled along with the smooth ones. Fluid flow and heat transfer simulations are conducted with COMSOL Multiphysics. Roughness is modeled as triangular obstructions on one of the plates ...
Elliptical Pin Fins as an Alternative to Circular Pin Fins for Gas Turbine Blade Cooling Applications Part 2 Wake Flow Field Measurements and Visualization Using Particle Image Velocimetry
Uzol, Oğuz (null; 2001-06-07)
Extensive wake flow field measurements and visualizations are conducted using particle image velocimetry (PIV) inside the wakes of the elliptical and circular pin fin arrays in order to better understand the flow physics and the loss mechanisms of these devices. The true-mean velocity field inside the wake two diameters downstream of the pin fin arrays is obtained by collecting and ensemble averaging a large number of PIV samples in the midplane of the test section. Additional experiments are also conducted...
Numerical simulation of thermal convection under the influence of a magnetic field by using solenoidal bases
Yarımpabuç, Durmuş; Tarman, Işık Hakan; Department of Engineering Sciences (2011)
The effect of an imposed magnetic field on the thermal convection between rigid plates heated from below under the influence of gravity is numerically simulated in a computational domain with periodic horizontal extent. The numerical technique is based on solenoidal basis functions satisfying the boundary conditions for both velocity and induced magnetic field. The expansion bases for the thermal field are also constructed to satisfy the boundary conditions. The governing partial differential equations are ...
Citation Formats
M. E. Özet, “Improving flow structure and natural convection within fin spacings of plate fin heat sinks,” M.S. - Master of Science, Middle East Technical University, 2015.