Heat Sinks With Enhanced Heat Transfer Capability for Electronic Cooling Applications

2005 ◽  
Vol 128 (3) ◽  
pp. 285-290 ◽  
Author(s):  
Evan Small ◽  
Sadegh M. Sadeghipour ◽  
Mehdi Asheghi
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Heat Sink ◽  
Engineering Students ◽  
Electronic Cooling ◽  
Heat Sinks ◽  
Optimum Number ◽  
Transfer Capability ◽  
Improve Heat Transfer ◽  
Heat Transfer Capability

In a competition at Carnegie Mellon University, the mechanical engineering students designed and manufactured 27 heat sinks. The heat sinks were then tested for thermal performance in cooling a mock processor. A heat sink with three rows of 9, 8, and 9 dimpled rectangular fins in staggered configuration performed the best, while having the least total volume (about 25% less than the set value). Validation of the observed thermal performance of this heat sink by experimentation and numerical simulations has motivated the present investigation. Thermal performance of the heat sinks with and without dimples have been evaluated and compared. Results of both the measurements and simulations indicate that dimples do in fact improve heat transfer capability of the heat sinks. However, dimples cause more pressure drop in the air flow. Keeping the total volume of the heat sink and the height of the fins constant and changing the number of the fins and their arrangement show that there is an optimum number of fins for the best performance of the heat sink. The optimum fin numbers are different for inline and staggered arrangements.

Heat Transfer Enhancement in the Heat Sinks for Electronic Cooling Applications

2005 ◽  
Author(s):  
Evan Small ◽  
Sadegh M. Sadeghipour ◽  
Mehdi Asheghi
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Transfer Enhancement ◽  
Heat Sink ◽  
Engineering Students ◽  
Electronic Cooling ◽  
Heat Sinks ◽  
Optimum Number ◽  
Transfer Enhancement

In a design competition by the mechanical engineering students at Carnegie Mellon University, which was the design of heat sinks for electronic cooling applications, twenty seven heat sinks were designed and tested for thermal performance. A heat sink with three rows of 9, 8, and 9 dimpled rectangular fins (staggered configuration) demonstrated the best performance in the test. This heat sink even had the least total volume (about 25% less than the set value). This paper reports on an effort made to verify and quantify the role of dimples on heat transfer enhancement of the heat sinks. This includes measurements and simulations of the thermal fluid properties of the heat sinks with and without dimples. Results of both the measurements and simulations indicate that dimples do in fact improve heat transfer capability of the heat sinks. Albeit, dimpled fins cause more pressure drop in air along the heat sink. Keeping the total volume of the heat sink and the height of the fins constant and changing the number of the fins and their arrangement show that there exist an optimum number of fins for the best performance of the heat sink. However, this number of fins is different for inline and staggered arrangements. To check the role of the roughness type on the heat transfer behavior of the fins, a heat sink with twenty-seven bumped fins with inline arrangement was also simulated. Results indicated that bumps increase both thermal resistance and pressure drop relative to that of the heat sinks with plain fins.

Computational fluid dynamics for thermal performance of a water-cooled minichannel heat sink with different chip arrangements

2014 ◽  
Vol 24 (4) ◽  
pp. 797-810 ◽  
Author(s):  
Gongnan Xie ◽  
Shian Li ◽  
Bengt Sunden ◽  
Weihong Zhang
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Thermal Performance ◽  
Heat Sink ◽  
Electronic Devices ◽  
Heat Sinks ◽  
Bottom Surface ◽  
Moderate Pressure ◽  
Content Type

Purpose – With the development of electronic devices, including the desires of integration, miniaturization, high performance and the output power, cooling requirement of chips have been increased gradually. Water-cooled minichannel is an effective cooling technology for cooling of heat sinks. The minichannel flow geometry offers large surface area for heat transfer and a high convective heat transfer coefficient with only a moderate pressure loss. The purpose of this paper is to analyze a minichannel heat sink having the bottom size of 35 mm×35 mm numerically. Two kinds of chip arrangement are investigated: diagonal arrangement and parallel arrangement. Design/methodology/approach – Computational fluid dynamics (CFD) technique is used to investigate the flow and thermal fields in forced convection in a three-dimensional minichannels heat sink with different chip arrangements. The standard k-e turbulence model is applied for the turbulence simulations on the minichannel heat sink. Findings – The results show that the bottom surface of the heat sink with various chip arrangements will have different temperature distribution and thermal resistance. A suitable chip arrangement will achieve a good cooling performance for electronic devices. Research limitations/implications – The fluid is incompressible and the thermophysical properties are constant. Practical implications – New and additional data will be helpful as guidelines in the design of heat sinks to achieve a good thermal performance and a long lifetime in operation. Originality/value – In real engineering situations, chips are always placed in various manners according to design conditions and constraints. In this case the assumption of uniform heat flux is acceptable for the surfaces of the chips rather than for the entire bottom surface of the heat sink.

Heat Transfer Analysis of Supercritical Methane in Microchannels with Different Geometric Configurations On High Power Electromechanical Actuator

2022 ◽  
Author(s):  
Zhigang Gao ◽  
Tianhu Wang ◽  
Yuxin Yang ◽  
Xiaolong Shang ◽  
Junhua Bai ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
High Power ◽  
Heat Sink ◽  
Heat Removal ◽  
Electrical Equipment ◽  
Heat Sinks ◽  
Electromechanical Actuator ◽  
Regenerative Cooling ◽  
Geometric Configurations

Abstract The issue of regenerative cooling is one of the most important key technologies of flight vehicles, which is applied into both the engine and high-power electrical equipment. One pattern of regenerative cooling channels is the microchannel heat sinks, which are thought as a prospective means of improving heat removal capacities on electrical equipment of smaller sizes. In this paper, three numerical models with different geometric configurations, namely straight, zigzag, and sinusoid respectively, are built to probe into the thermal hydraulic performance while heat transfer mechanism of supercritical methane in microchannel heat sinks for the heat removal of high-power electromechanical actuator is also explored. In addition, some crucial influence factors on heat transfer such as inlet Reynolds number, operating pressure and heating power are investigated. The calculation results imply the positive effect of wavy configurations on heat transfer and confirm the important effect of buoyancy force of supercritical methane in channels. The heat sinks with wavy channel show obvious advantages on comprehensive thermal performance including overall thermal performance parameter ? and thermal resistance R compared with that of the straight one. The highest Nu and average heat transfer coefficient am appear in the heat sink with zigzag channels, but the pumping power of the heat sink with sinusoidal channels is lower due to the smaller flow loss.

An Experimental Study on the Effect of Configuration of Multiple Microchannels on Heat Removal for Electronic Cooling

2010 ◽  
Author(s):  
Jingru Zhang ◽  
Shaurya Prakash ◽  
Yogesh Jaluria ◽  
Lei Lin
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Heat Removal ◽  
Electronic Cooling ◽  
Heat Sinks ◽  
Flow Loop ◽  
Labview Software ◽  
Chemical Etch ◽  
Potential Applications

This paper presents the design, fabrication, and characterization of three different configurations of multiple microchannel heat sink devices to improve their overall cooling efficiency for potential applications in electronic cooling. A fabrication and packaging process based on standard UV-lithography, wet etching, and bonding was developed to allow a rapid parametric study. An anisotropic chemical etch with potassium hydroxide, water, and isopropanol is used to fabricate microchannels on (110)-oriented silicon wafers. PDMS (Polydimethylsiloxane) was tested as the cover of microchannels due to its mechanical flexibility. It is transparent so that the microchannel flow can be visualized using a microscope. An open flow loop, which consists of syringe pump and a power supply, was designed to test the heat sinks with different configurations. Temperature data were collected at different locations by a Data Acquisition (DAQ) system and recorded by Labview software to investigate the heat transfer characteristics of the heat sink. Three heat sinks, with different configurations, were tested. They all included microchannels of width 50 μm, depth 60 μm, and fin width 200 μm. Some Typical results on heat transfer are presented, along with discussion on the efficiency for heat removal.

Metallic Nanoemulsion for Microchannel Heat-Sink

2016 ◽  
Author(s):  
Yoshikazu Hayashi ◽  
Gordon Yip ◽  
Yoon Jo Kim ◽  
Jong-Hoon Kim
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Specific Heat ◽  
Heat Sink ◽  
Effective Medium Theory ◽  
Working Fluid ◽  
Microchannel Heat Sink ◽  
Viscosity Change ◽  
Transfer Capability ◽  
Heat Transfer Capability

Galinstan is a eutectic alloy of gallium, indium, and tin, of which thermal conductivity is ∼27 times higher than that of water, while the dynamic viscosity is only twice. Thus, heat transfer coefficient can be remarkably enhanced with a small penalty of pumping power. However, the direct use of galinstan can suffer from practical issues such as oxidation and low specific heat. Therefore, galinstan is mixed with a coolant as an additive to form a colloidal fluid; i.e., dispersion of nanoscale galinstan droplets in a coolant to enhance the thermal conductivity. It is expected that this “metallic nanoemulsion” can contribute to substantial improvement in heat transfer capability. Also, the common issues with colloidal fluids such as rapid sedimentation, erosion, and clogging, can be minimized by the “fluidity” of the liquid metal. It was shown that ultrasonic emulsification can yield few hundreds scale nanodroplets. However, the long exposure of galinstan to oxygen in water inevitably results in severe oxidation of the droplets. Theoretical analysis was also conducted to examine the feasibility of the metallic nanoemulsion as a microchannel heat-sink working fluid. Effective medium theory was used to evaluate the thermal conductivity of the mixture. The viscosity change was also predicted considering both the viscosity of dispersed phase and interaction between the droplets. Under one-dimensional laminar flow assumption, mass, momentum, and energy conservation equations were analytically solved. The effect of high thermal conductivity of galinstan was evident; the convection heat transfer capability was greatly enhanced, while the viscosity increase due to the nanoscale blending and the low specific heat of galinstan counteracts and reduce the flow rate and thus increase the caloric thermal resistance.

Development of a Mini Heat Sink Model With Homogeneous Heat Transfer Capability

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
J. F. Zhou
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Heating Surface ◽  
Bottom Surface ◽  
Cooling Power ◽  
Local Pressure ◽  
Pressure Drops ◽  
Transfer Capability ◽  
Length Width ◽  
Heat Transfer Capability

A model of mini heat sink with microchannels was developed to obtain homogeneous heat transfer capability. The channels are constructed in the form of eight triangular arrays based on a square substrate. Air is sucked from the periphery to the center of the substrate by a vacuum pump and heat transferred from the bottom surface of substrate can be removed by air flowing through channels. Corresponding to the given heat transfer power and the target temperature of substrate, the relationship among length, width and depth of channel was analytically established. By numerical simulation, local pressure drops at the joint of channels and air duct are first obtained and then the dimensions of each channel in a triangular array can be determined one by one. The investigation reveals that the widths of channels will vary with their depths, lengths and pressure differences between two ends. Since all channels are required for the same cooling power, the homogeneous heat transfer of heat sink can be realized. By assembling a certain number of heat sink units, the area of dissipation of heat sink can be enlarged and contoured to fit close to heating surface.

scholarly journals Experimental analysis of effect of base with different inner geometries filled nano PCM for the thermal performance of the plate fin heat sink

2021 ◽  
pp. 243-243
Author(s):  
Periyannan Lakshmanan ◽  
Saravanan Periyasamy ◽  
Mohan Raman
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Reynolds Number ◽  
Phase Shift ◽  
Experimental Research ◽  
Thermal Performance ◽  
Heat Sink ◽  
Electronic Devices ◽  
Base Plate ◽  
Heat Sinks

Experimental research demonstrates the performance of electronic devices on plate fin heat sinks in order to guarantee that operating temperatures are kept as low as possible for reliability. Paraffin wax (PCM) is a substance that is used to store energy and the aluminum plate fin cavity base is chosen as a Thermal Conductivity Enhancer (TCEs). The effects of PCM material (Phase shift material), cavity form base (Rectangular, Triangular, Concave and Convex) with PCM, Reynolds number (Re= 4000-20000) on heat transfer effectiveness of plate fin heat sinks were experimentally explored in this research. The thermal performance of concave base plate fin heat sink with PCM is increased up to 7.8% compared to other cavity base heat sinks.

Effect of Flow Bypass on the Performance of Longitudinal Fin Heat Sinks

1994 ◽  
Vol 116 (3) ◽  
pp. 206-211 ◽  
Author(s):  
R. A. Wirtz ◽  
Weiming Chen ◽  
Ronghua Zhou
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Thermal Performance ◽  
Heat Sink ◽  
Design Guidelines ◽  
Heat Sinks ◽  
Air Cooling ◽  
Regular Array ◽  
Electronic Package ◽  
And Performance

Heat transfer experiments are reported on the thermal performance of longitudinal fin heat sinks attached to an electronic package which is part of a regular array of packages undergoing forced convection air cooling. The effect of coolant bypass on the performance of the heat sink is assessed and performance correlations for reduced heat transfer due to this effect are developed. These correlations are used to develop design guidelines for optimal performance.

Thermal Performance of the Mini-Loop Heat Pipe (LHP)

2009 ◽  
Author(s):  
K. Tanaka ◽  
M. Katsuta ◽  
Y. Ohuchi ◽  
K. Saitho
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Physical Development ◽  
Working Fluid ◽  
Loop Heat Pipe ◽  
Transfer Capability ◽  
Heat Transfer Capability ◽  
Basic Equations ◽  
Test Result

In this paper, we describe the outline of experimental manufacture of the LHP. This LHP is made of a copper. The evaporator is φ19×95mm, the vapor tube is φ5×300mm, the condenser is φ3.5×600mm and the liquid tube is φ 3.5×300mm. The wick is made of the sintering copper. The working fluid is methanol. Second, we describe the test result of heat transfer capability of this LHP. Finally, I describe the basic equations that resolve the physical development of the LHP and how to estimate the each temperatures of the LHP.

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