Experimental investigation of uninterrupted and interrupted microchannel heat sinks

Download

index.pdf

Date

2012

Author

Ulu, Ayşe Gözde

Metadata

Show full item record

Item Usage Stats

199
views

399
downloads

Experimental measurements are conducted on uninterrupted and interrupted aluminum microchannel heat sinks of 300, 500, 600 and 900 μm channel widths. Two different versions of interrupted channels are tested; with single interruption and with 7 interruptions. Distilled water is used as the working fluid and tests are conducted at volumetric flow rates in a range of 0.5-1.1 lpm. Thermoelectric foils are used to supply uniformly distributed heat load to the heat sinks such that for all the tests the heat removed by water is kept constant at 40 W. Pressure drop and temperature increase are measured along the channels of different configurations for a number of different flow rates. For the interrupted channels thermal boundary layers re-initialize at the leading edge of each interrupted fin, which decreases the overall boundary layer thickness. Also the flow has been kept as developing, which results in better heat transfer performance. Due to the separation of the flow into branches, secondary flows appear which improves the mixing of the stream. Advanced mixing of the flow also enhances the thermal performance. In the experiments, it is observed that interruption of channels improved the thermal performance over the uninterrupted counterparts up to 20% in average Nusselt number, for 600 micron-wide channels. The improvement of average Nusselt number between the single interrupted and multi interrupted channels reached a maximum value of 56% for 500 micron-wide channels. This improvement did not cause a high pressure drop deviation between the uninterrupted and interrupted microchannels even for the maximum volumetric flow rate of 1.1 lpm. Highest pressure drop through the channels was measured as 0.07 bar, which did not require to change the pump. In the tests, maximum temperature difference between the inlet of the fluid and the base of the channel is observed as 32.8°C, which is an acceptable value for electronic cooling applications.

Subject Keywords

Mechanical Engineering.

URI

http://etd.lib.metu.edu.tr/upload/12614227/index.pdf
https://hdl.handle.net/11511/21370

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Experimental investigation and numerical analysis of microchannel heatsinks for phased array radar cooling application Alpsan, Emrah; Sert, Cüneyt; Department of Mechanical Engineering (2008) Experimental measurements and numerical simulations have been performed on copper and aluminum microchannel heatsinks of 300, 420, 500, and 900 μm channel widths. The heatsinks have been designed specifically for use with T/R (transmit/receive) module cooling applications of military phased array radars. An analytical calculation was also performed to aid in the design methodology. Distilled water was used as the coolant with flow rates ranging from 0.50 lpm (liters per minute) to 1.00 lpm. Local heat fluxe...
Uncertainty Analysis of Heat Transfer Predictions Using Statistically Modeled Data From a Cooled 1-1/2 Stage High-Pressure Transonic Turbine Kahveci, Harika Senem (ASME International, 2014-06-01) This paper compares predictions from a 3D Reynolds-averaged Navier-Stokes code and a statistical representation of measurements from a cooled 1-1/2 stage high-pressure transonic turbine to quantify predictive process sensitivity. A multivariable regression technique was applied to both the inlet temperature measurements obtained at the inlet rake, the wall temperature, and heat transfer measurements obtained via heat-flux gauges on the blade airfoil surfaces. By using the statistically modeled temperature p...
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 ...
Analysis of single phase convective heat transfer in microtubes and microchannels Çetin, Barbaros; Yüncü, Hafit; Department of Mechanical Engineering (2005) Heat transfer analysis of two-dimensional, incompressible, constant property, hydrodynamically developed, thermally developing, single phase laminar flow in microtubes and microchannels between parallel plates with negligible axial conduction is performed for constant wall temperature and constant wall heat flux thermal boundary conditions for slip flow regime. Fully developed velocity profile is determined analytically, and energy equation is solved by using finite difference method for both of the geometr...
Experimental investigation of a spherical solar collector Bakır, Öztekin; Yamalı, Cemil; Department of Mechanical Engineering (2006) The purpose of this study is to investigate the performance of a spherical solar collector by using numerical and experimental methods. For this analysis, equations were obtained by choosing appropriate control volumes in the system and applying The First Law of Thermodynamics. The experiments were realized at four different mass flow rates and non-flow situation. For the numerical simulation of the system, a computer program in Mathcad was written. Another computer program in Mathcad was written for the va...

Citation Formats

A. G. Ulu, “Experimental investigation of uninterrupted and interrupted microchannel heat sinks,” M.S. - Master of Science, Middle East Technical University, 2012.