Heat Transfer in Water-Cooled Silicon Carbide Milli-Channel Heat Sinks for High Power Electronic Applications

2005 ◽  
Vol 127 (1) ◽  
pp. 59-65 ◽  
Author(s):  
C. Bower ◽  
A. Ortega ◽  
P. Skandakumaran ◽  
R. Vaidyanathan ◽  
T. Phillips
Keyword(s):  
Heat Transfer ◽  
Silicon Carbide ◽  
Single Channel ◽  
Water Soluble ◽  
Heat Sinks ◽  
Transfer Coefficients ◽  
Channel Diameter ◽  
Water Soluble Polymer ◽  
Freeform Fabrication ◽  
Heat Transfer Coefficients

Heat transfer and fluid flow in a novel class of silicon carbide water-cooled milli-channel heat sinks were investigated. The heat sinks were manufactured using an extrusion freeform fabrication (EFF) rapid prototyping technology and a water-soluble polymer material. Rectangular heat exchangers with 3.2 cm×2.2 cm planform area and varying thickness, porosity, number of channels, and channel diameter were fabricated and tested. The perchannel Reynolds number places the friction coefficients in the developing to developed hydrodynamic regime, and showed excellent agreement with laminar theory. The overall heat transfer coefficients compared favorably with the theory for a single channel row but not for multiple rows.

Heat Transfer in Water-Cooled Silicon Carbide Milli-Channel Heat Sinks for High Power Electronic Applications

2003 ◽  
Author(s):  
C. Bower ◽  
A. Orgega ◽  
P. Skandakumaran ◽  
R. Vaidyanathan ◽  
T. Phillips
Keyword(s):  
Heat Transfer ◽  
Silicon Carbide ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Flow Direction ◽  
Water Soluble ◽  
Heat Sinks ◽  
Transfer Coefficients ◽  
Channel Diameter ◽  
Water Soluble Polymer

Heat transfer and fluid flow in a novel class of water-cooled milli-channel heat sinks are investigated. The heat sinks are manufactured using an extrusion freeform fabrication (EFF) rapid prototyping technology and a water-soluble polymer material. EFF permits the fabrication of geometrically complex, three-dimensional structures in non-traditional materials. Silicon carbide, SiC, is TEC-matched to silicon and is an ideal material for heat exchangers that will be mounted directly to heat dissipating electronic packages. This paper presents experimental results on the heat transfer and flow in small SiC heat exchangers with multiple rows of parallel channels oriented in the flow direction. Rectangular heat exchangers with 3.2 cm × 2.2 cm planform area and varying thickness, porosity, number of channels, and channel diameter were fabricated and tested. Overall heat transfer and pressure drop coefficients in single-phase flow regimes are presented and analyzed. The per channel Reynolds number places the friction coefficients in the developing to developed hydrodynamic regime, and showed excellent agreement with laminar theory. The overall heat transfer coefficients for a single row SiC heat exchanger compared favorably with a validation heat exchanger fabricated from copper, however the heat transfer coefficient in multiple row heat sinks did not agree well with the laminar theory.

Experimental Study of Single-Phase Heat Transfer in Circular Milli-Channels for Cooling of Micro Components

2005 ◽  
Author(s):  
Antonio Ramos ◽  
Antonio J. Bula ◽  
Maria Cely
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Single Phase ◽  
Flow Direction ◽  
Heat Sinks ◽  
Rectangular Plates ◽  
Transfer Coefficients ◽  
Channel Diameter ◽  
Heat Transfer Coefficients ◽  
Experimental Process

The increase of processing speed in applications such as servers, laptops and workstations requires heat-sinking technologies with higher levels of power dissipation than the current methods. For this reason, this paper presents an experimental study of heat transfer in water-cooled milli - channel heat sinks. The experimental process consists of fabrication and testing of rectangular plates with multiple parallel channels oriented in the flow direction. Variations in the number of channels, channel diameter, and volumetric flow were considered in order to study the conjugate heat transfer phenomena. Overall heat transfer coefficients in single-phase flow regimes are presented and analyzed.

A Study of Forced Convection Direct Air Cooling in the Downstream Vicinity of Heat Sinks

1990 ◽  
Vol 112 (3) ◽  
pp. 234-240 ◽  
Author(s):  
G. L. Lehmann ◽  
S. J. Kosteva
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Heat Sink ◽  
Convection Heat Transfer ◽  
Heat Sinks ◽  
Air Cooling ◽  
Transfer Coefficients ◽  
Packaging System ◽  
Transfer Rates ◽  
Heat Transfer Coefficients

An experimental study of forced convection heat transfer is reported. Direct air cooling of an electronics packaging system is modeled by a channel flow, with an array of uniformly sized and spaced elements attached to one channel wall. The presence of a single or complete row of longitudinally finned heat sinks creates a modified flow pattern. Convective heat transfer rates at downstream positions are measured and compared to that of a plain array (no heat sinks). Heat transfer rates are described in terms of adiabatic heat transfer coefficients and thermal wake functions. Empirical correlations are presented for both variations in Reynolds number (5000 < Re < 20,000) and heat sink geometry. It is found that the presence of a heat sink can both enhance and degrade the heat transfer coefficient at downstream locations, depending on the relative position.

Cryogenic Single-Phase Heat Transfer in a Microscale Pin Fin Heat Sink

2013 ◽  
Author(s):  
Eric D. Truong ◽  
Erfan Rasouli ◽  
Vinod Narayanan
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Sink ◽  
Single Phase ◽  
Flow Direction ◽  
Heat Sinks ◽  
Variable Cross ◽  
Transfer Coefficients ◽  
Pin Fin ◽  
Heat Transfer Coefficients

A combined experimental and computational fluid dynamics study of single-phase liquid nitrogen flow through a microscale pin-fin heat sink is presented. Such cryogenic heat sinks find use in applications such as high performance computing and spacecraft thermal management. A circular pin fin heat sink in diameter 5 cm and 250 micrometers in depth was studied herein. Unique features of the heat sink included its variable cross sectional area in the flow direction, variable pin diameters, as well as a circumferential distribution of fluid into the pin fin region. The stainless steel heat sink was fabricated using chemical etching and diffusion bonding. Experimental results indicate that the heat transfer coefficients were relatively unchanged around 2600 W/m2-K for flow rates ranging from 2–4 g/s while the pressure drop increased monotonically with the flow rate. None of the existing correlations in literature on cross flow over a tube bank or micro pin fin heat sinks were able to predict the experimental pressure drop and heat transfer characteristics. However, three dimensional simulations performed using ANSYS Fluent showed reasonable (∼7 percent difference) agreement in the average heat transfer coefficients between experiments and CFD simulations.

An Experimental Study of Pin Fin Heat Sinks and Determination of End Wall Heat Transfer

2003 ◽  
Author(s):  
Massimiliano Rizzi ◽  
Ivan Catton
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Heat Sink ◽  
Optimization Methods ◽  
Heat Sinks ◽  
Base Region ◽  
Transfer Coefficients ◽  
Media Type ◽  
Pin Fin ◽  
Heat Transfer Coefficients

An experimental study of a pin fin heat sink was carried out in support of the development of heat sink optimization methods requiring more detailed measurements be made. Measurements of heat flux and temperature are used to separately determine heat transfer coefficients for the pins and the base region between the pins. Three pitch to diameter ratios (distance from pin center to pin center measured diagonally) were studied: P/d = 3/1, 9/4, 3/2. Heat generation was accomplished using cartridge heaters inserted into a copper block. The high thermal conductivity of the copper ensured that the surface beneath the heat sink would be at a constant temperature. The cooling fluid was air and the experiments were conducted with a Reynolds numbers based on a porous media type hydraulic diameter ranging from 500 to 25000. The channel had a shroud that touches the fin tips, eliminating any flow bypass. The pin surface heat transfer coefficients match the values reported by Kays and London and by Zukauskas. The base region heat transfer coefficients were, surprisngly, larger than the pin values.

Parametric Dependence of Annular Flow Heat Transfer in Microgaps

2010 ◽  
Author(s):  
Emil Rahim ◽  
Avram Bar-Cohen
Keyword(s):  
Heat Transfer ◽  
Annular Flow ◽  
Forced Flow ◽  
Working Fluid ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Channel Diameter ◽  
Parametric Dependence ◽  
Heat Transfer Coefficients ◽  
High Heat Transfer

Forced flow of refrigerants and dielectric liquids, undergoing phase change in a heated microgap channel between chips or in parallel microchannels in a compact cooler, is a promising candidate for the thermal management of advanced semiconductor devices. It has been found that Annular flow is the dominant flow regime in such miniature channels and that relatively high heat transfer coefficients are encountered in the moderate-to-high quality sections of such channels. Following a discussion of flow regimes and thermal characteristics of miniature channels, attention turns to exploring the parametric dependence of annular flow thermal transport in microgaps including the effects of channel diameter, mass flux, and working fluid on the two-phase heat transfer coefficients.

Effects of Channel Aspect Ratio on Convective Heat Transfer in an Electronics Cooling Heat Sink Having Agitation and Fan-Induced Throughflow

2013 ◽  
Author(s):  
Smita Agrawal ◽  
Longzhong Huang ◽  
Terrence Simon ◽  
Mark North ◽  
Tianhong Cui
Keyword(s):  
Heat Transfer ◽  
Aspect Ratio ◽  
Heat Sink ◽  
Single Channel ◽  
Electronics Cooling ◽  
Heat Sinks ◽  
Channel Width ◽  
Channel Height ◽  
Transfer Coefficients ◽  
Multiple Channel

Fan-driven throughflow is frequently used for convective cooling of electronics. Channels with walls behaving like fins are common. In the present study, the flow inside the channels is agitated by means of translationally oscillating plates called agitators. Effectiveness of agitation by oscillating blades is found to be dependent on the channel width, a parameter studied herein. Heat sinks having narrower channels have a greater number of channels in total for the fixed size of heat sink and therefore greater heat transfer area than heat sinks with wider channels. Thus, with the same channel height, as the aspect ratio increases, channel width decreases, and it is found that opportunities for agitation are reduced and the generated turbulence is more strongly damped, thus reducing heat transfer coefficients. A study was carried out to find direction toward an optimal number of channels for a given heat sink using the agitation strategy. As part of the study, fluid damping and power consumption to drive the agitator assembly were addressed. The study was done numerically using ANSYS FLUENT on a representative single channel of the heat sink and the results were extended to the full size, multiple-channel heat sink system. Recommendations for moving toward an optimum geometry, based on thermal performance and agitator power are made.

Experiments and Modeling of the Heat Transfer of In-Line Square Pin Fin Heat Sinks With Top By-Pass Flow

2002 ◽  
Author(s):  
M. Baris Dogruoz ◽  
Mario Urdaneta ◽  
Alfonso Ortega
Keyword(s):  
Heat Transfer ◽  
Experimental Results ◽  
Heat Sinks ◽  
Transfer Coefficients ◽  
Clearance Ratio ◽  
One Dimensional ◽  
Pin Fin ◽  
Heat Transfer Coefficients ◽  
Approach Velocity ◽  
Good Agreement

This paper presents experimental results on the heat transfer characteristics of in-line square pin fin heat sinks with and without top by-pass. A self-consistent set of aluminum heat sinks were utilized, where the pin height was varied from 12.5 mm to 22.5 mm, the pin pitch was varied from 3.4 mm to 5.8 mm and the base dimensions were kept fixed at 25 × 25 mm. The overall base to ambient thermal resistance was measured as a function of Reynolds number and bypass height. Experimental results were then compared with predictions based on a simple one-dimensional “two-branch by-pass model”. Comparisons were made with the data using heat transfer coefficients available in the literature for infinitely long tube bundles. It was shown that there is a good agreement between the temperature predictions based on the model and the experimental data at high approach velocities for tall heat sinks, however the discrepancy between the computations and experiments increases as the approach velocity and heat sink height decrease. The validated model was used to identify optimum pin spacing as a function of clearance ratio.

Sign in / Sign up

Export Citation Format

Share Document