Thermal Design Criteria for Extraordinary Performance of Devices Cooled by Microchannel Heat Sink

2010 ◽  
Vol 2 (4) ◽  
Author(s):  
Dylan Farnam ◽  
Bahgat Sammakia ◽  
Kanad Ghose
Keyword(s):  
Contact Area ◽  
Heat Sink ◽  
Heat Removal ◽  
Thermal Design ◽  
Heat Sinks ◽  
Design Criteria ◽  
Microchannel Heat Sink ◽  
Device Architecture ◽  
Microchannel Heat Sinks ◽  
Thermal Solution

Increasing power dissipation in microprocessors and other devices is leading to the consideration of more capable thermal solutions than the traditional air-cooled fin heat sinks. Microchannel heat sinks (MHSs) are promising candidates for long-term thermal solution given their simplicity, performance, and the development of MHS-compatible 3D device architecture. As the traditional methods of cooling generally have uniform heat removal on the contact area with the device, thermal consequences of design have traditionally been considered only after the layout of components on a device is finalized in accordance with connection and other criteria. Unlike traditional cooling solutions, however, microchannel heat sinks provide highly nonuniform heat removal on the contact area with the device. This feature is of utmost importance and can actually be used quite advantageously, if considered during the design phase of a device. In this study, simple thermal design criteria governing the general placement of components on devices to be cooled by microchannel heat sink are developed and presented. These thermal criteria are not meant to supersede connection and other important design criteria but are intended as a necessary and valuable supplement. Full-scale numerical simulations of a device with a realistic power map cooled by microchannel heat sink prove the effectiveness of the criteria, showing large reduction in maximum operating temperature and harmful temperature gradients. The simulations further show that the device and microchannel heat sink can dissipate a comparatively high amount of power, with little thermal danger, when design considers the criteria developed herein.

Enhanced Thermal Transport in Microchannel Using Oblique Fins

2012 ◽  
Vol 134 (10) ◽  
Author(s):  
Y. J. Lee ◽  
P. S. Lee ◽  
S. K. Chou
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Heat Transfer Enhancement ◽  
Heat Sink ◽  
Heat Sinks ◽  
Maximum Temperature ◽  
Working Fluid ◽  
Microchannel Heat Sink ◽  
Transfer Enhancement ◽  
Microchannel Heat Sinks

Sectional oblique fins are employed, in contrast to continuous fins in order to modulate the flow in microchannel heat sinks. The breakage of a continuous fin into oblique sections leads to the reinitialization of the thermal boundary layer at the leading edge of each oblique fin, effectively reducing the boundary layer thickness. This regeneration of entrance effects causes the flow to always be in a developing state, thus resulting in better heat transfer. In addition, the presence of smaller oblique channels diverts a small fraction of the flow into adjacent main channels. The secondary flows created improve fluid mixing, which serves to further enhance heat transfer. Both numerical simulations and experimental investigations of copper-based oblique finned microchannel heat sinks demonstrated that a highly augmented and uniform heat transfer performance, relative to the conventional microchannel, is achievable with such a passive technique. The average Nusselt number, Nuave, for the copper microchannel heat sink which uses water as the working fluid can increase as much as 103%, from 11.3 to 22.9. Besides, the augmented convective heat transfer leads to a reduction in maximum temperature rise by 12.6 °C. The associated pressure drop penalty is much smaller than the achieved heat transfer enhancement, rendering it as an effective heat transfer enhancement scheme for a single-phase microchannel heat sink.

Experimental and Numerical Study of Transient Electronic Chip Cooling by Liquid Flow in Microchannel Heat Sink

2010 ◽  
Author(s):  
Jingru Zhang ◽  
Tiantian Zhang ◽  
Yogesh Jaluria
Keyword(s):  
Liquid Flow ◽  
Heat Sink ◽  
Single Channel ◽  
Numerical Study ◽  
Numerical Models ◽  
Heat Removal ◽  
Heat Fluxes ◽  
Heat Sinks ◽  
Chip Cooling ◽  
Microchannel Heat Sinks

Cooling of electronic chips has become a critical aspect in the development of electronic devices. Overheating may cause the malfunction or damage of electronics and the time needed for heat removal is important. In this paper, an experimental setup and numerical model was developed to test the effects of different parameters and their influence on the transient electronic chip cooling by liquid flow in microchannel heat sinks. The temperature change with time of the system for different heat fluxes at different flow was determined, from which the response time can be obtained. Three different configurations of multi-microchannel heat sinks were tested during the experiment. Numerical models were then developed to simulate the transient cooling for two of the configurations. A good agreement between the experimental data and numerical results showed that single-channel models are capable of simulating the thermal behavior of the entire heat sink by applying appropriate assumptions and boundary conditions.

scholarly journals Experimental and Numerical Thermal Analysis of Multi-Layered Microchannel Heat Sink for Concentrating Photovoltaic Application

Energies ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 122 ◽  
Author(s):  
Idris Al Siyabi ◽  
Sourav Khanna ◽  
Senthilarasu Sundaram ◽  
Tapas Mallick
Keyword(s):  
Heat Source ◽  
Heat Sink ◽  
Heat Removal ◽  
Heat Sinks ◽  
Heat Transfer Fluid ◽  
Microchannel Heat Sink ◽  
Source Temperature ◽  
Number Of Layers ◽  
Heat Source Temperature ◽  
Heating Load

Concentrating photovoltaic has a major challenge due to the high temperature raised during the process which reduces the efficiency of the solar cell. A multi-layered microchannel heat sink technique is considered more efficient in terms of heat removal and pumping power among many other cooling techniques. Thus, in the current work, multi-layered microchannel heat sink is used for concentrating photovoltaic cooling. The thermal behavior of the system is experimentally and numerically investigated. The results show that in extreme heating load of 30 W/cm2 with heat transfer fluid flow rate of 30 mL/min, increasing the number of layers from one to four reduces the heat source temperature from 88.55 to 73.57 °C. In addition, the single layered MLM heat sink suffers from the highest non-uniformity in the heat source temperature compared to the heat sinks with the higher number of layers. Additionally, the results show that increasing the number of layers from one to four reduces the pressure drop from 162.79 to 32.75 Pa.

Numerical Investigations of the Effect of Flow Arrangement and Number of Layers on the Performance of Multi-Layer Microchannel Heat Sinks

2015 ◽  
Author(s):  
M. B. Effat ◽  
M. S. AbdelKarim ◽  
O. Hassan ◽  
M. Abdelgawad
Keyword(s):  
Heat Flux ◽  
Temperature Distribution ◽  
Heat Sink ◽  
Single Layer ◽  
Heat Sinks ◽  
Uniform Heat Flux ◽  
Microchannel Heat Sink ◽  
Electronic Components ◽  
Number Of Layers ◽  
Microchannel Heat Sinks

With the advance of miniaturization technology, more and more electronic components are placed onto small electronic chips. This leads to the generation of high amounts of thermal energy that should be removed for the safe operation of these electronic components. Microchannel heat sinks, where electronic chips are liquid cooled instead of the conventional air cooling techniques, were proposed as a means to improve cooling rates. Later on, double layer micro channel heat sinks were suggested as an upgrade to single layer microchannel heat sinks with a better thermal performance. In the present study the effects of increasing the number of layers of the microchannel heat sink to three-layers as well as the effect of changing the flow arrangements (counter and parallel flows) within the three channel layers on the thermal performance of the heat sink were investigated. In all investigated cases the temperature distribution over the base of the microchannel heat sink system and the total pressure drop are reported. A range of mass flow rates from 1×10−4 to 5×10−4 kg/s was considered. Uniform heat flux conditions were considered during the study. COMSOL Multiphysics finite element package was employed for the numerical analysis. Results indicate significant enhancement in the uniformity of the temperature on the processor surface when multi-layer channels were employed, compared to the single-layer case. The uniformity in the temperature distribution was accompanied by reduction of pressure drop across channels for the same mass flow rate and heat flux conditions. The counter flow arrangement showed the best temperature distribution with the uniform heat flux cases.

Development of MEMS Microchannel Heat Sinks for Micro/Nano Spacecraft Thermal Control

2002 ◽  
Author(s):  
Anthony D. Paris ◽  
Gajanana C. Birur ◽  
Amanda A. Green
Keyword(s):  
Heat Sink ◽  
Thermal Control ◽  
Hydraulic Performance ◽  
Heat Sinks ◽  
Performance Criteria ◽  
Working Fluid ◽  
High Heat Flux ◽  
Microchannel Heat Sink ◽  
Microchannel Heat Sinks ◽  
Spacecraft Thermal Control

MEMS-based microchannel heat sinks are being investigated at the Jet Propulsion Laboratory (JPL) for use in micro/nano spacecraft thermal control. The current stage of development focuses on the integration of microchannel heat sinks into spacecraft pumped cooling loops. Two microchannel heat sinks, adapted from a Stanford University Microfluidics Laboratory design, were fabricated at JPL and tested for thermal and hydraulic performance in a single-phase pumped cooling loop. The first microchannel heat sink design was demonstrated to remove heat fluxes of up to 25 W/cm2 with a maximum device temperature of less than 80 °C. Both the original and redesigned heat sinks where shown to meet hydraulic performance criteria requiring less than 1 psi pressure drop with water as the working fluid. It was concluded that the design methodology developed for this project produces microchannel heat sink devices capable of high heat flux removal in future micro/nano spacecraft thermal control architecture.

Constructal Design of Circular Multilayer Microchannel Heat Sinks

2018 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammad Reza Salimpour ◽  
Ahmed T. Al-Sammarraie ◽  
Azadeh Forouzandeh ◽  
Mahsa Farzaneh
Keyword(s):  
Heat Sink ◽  
Volume Fraction ◽  
Effective Means ◽  
Solid Volume Fraction ◽  
Heat Sinks ◽  
Constructal Theory ◽  
Maximum Temperature ◽  
Microchannel Heat Sink ◽  
Triple Layer ◽  
Microchannel Heat Sinks

Abstract Based on the constructal theory concepts, an investigation is carried out to optimize circular multilayer microchannels embedded inside a rectangular heat sink with different numbers of layers and flow configurations. The lower surface of the heat sink is uniformly heated, while both pressure drop and length of the microchannel are fixed. Also, the volume of the heat sink is kept fixed for all studied cases, while the effect of solid volume fraction is examined. All the dimensions of microchannel heat sinks are optimized in a way that the maximum temperature of the microchannel heat sink is minimized. The results emphasize that using triple-layer microchannel heat sink under optimal conditions reduces the maximum temperature about 10.3 °C compared to the single-layer arrangement. Further, employing counter flow configuration in double-layer microchannel improves its thermal performance, while this effect is less pronounced in the triple-layer architecture. In addition, it is revealed that the optimal design can be achieved when the upper channels of a multilayer microchannel heat sink have bigger diameters than the lower ones. Finally, it is observed while using two layers of microchannels is an effective means for cooling improvement, invoking more layers is far less effective and hence is not recommended.

A Three-Dimensional Simulation Analysis of Fluid Flow and Heat Transfer in Microchannel Heat Sinks with Different Structures

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jienan Shen ◽  
Xiuxiu Li ◽  
Yongsheng Zhu ◽  
Boya Zhang ◽  
Hang Guo ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Fluid Flow ◽  
Heat Sink ◽  
Simulation Analysis ◽  
Heat Sinks ◽  
Mixing Efficiency ◽  
Microchannel Heat Sink ◽  
Flow And Heat Transfer ◽  
Microchannel Heat Sinks

Abstract Numerical studies have been performed to analyze the fluid flow and heat transfer characteristics of nine microchannel heat sinks (MCHS) with different shapes and different arrangements of the ribs and cavities on the sidewalls, using three common shapes (square, triangle, and circular) of ribs or cavities as the basic structure in this work. The boundary conditions, governing equations, friction factor (f), Nusselt number (Nu), and performance evaluation criteria (ξ) were considered to determine which design was the best in terms of the heat transfer, the pressure drop, and the overall performance. It was observed that no matter how the circular ribs or cavities were arranged, its heat sink performance was better than the other two shapes for Reynolds number of 200–1000. Therefore, circular ribs or cavities can be considered as the best structure to improve the performance of MCHS. In addition, the heat sink performance of the microchannel heat sink with symmetrical circular ribs (MCHS-SCR) was improved by 31.2 % compared with the conventional microchannel heat sink at Re = 667. This was because in addition to the formation of transverse vortices in the channel, four symmetrical and reverse longitudinal vortices are formed to improve the mixing efficiency of the central fluid (low temperature) and the near-wall fluid (high temperature). Then, as the Reynolds number increases, the heat sink performance of MCHS-SCR dropped sharply. The heat sink performance of microchannel heat sinks with staggered ribs and cavities (MCHS-SCRC, MCHS-STRC, and MCHS-SSRC) exceeded that of MCHS-SCR. This indicated that the microchannel heat sink with staggered ribs and cavities was more suitable for high Reynolds number (Re > 800).

Comparison of the Effect of Embedded Grooves on the Heat Removal and Pressure Drop in Microchannel Heat Sinks

2011 ◽  
Author(s):  
Farnaz Faily ◽  
Haleh Shafeie ◽  
Omid Abouali
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Sink ◽  
Heat Removal ◽  
Heat Sinks ◽  
Coefficient Of Performance ◽  
Maximum Heat ◽  
Different Types ◽  
Microchannel Heat Sinks ◽  
Fin Thickness

This paper presents a numerical study for the single phase heat transfer of water in the heat sinks with different types of the grooved microchannels. The cross section of the grooves is either rectangular or arced shape. The grooves are embedded vertically in the side walls of the microchannel but for the floor, different orientation angles of the grooves in the range of 0–60° are investigated. As well, for the grooves on the floor of the channel, the chevron-shape is another pattern which has bee studied. A 3-D computational model is developed for each of the studied cases and the conjugate heat transfer in both solid and liquid is investigated. The governing equations are solved numerically to determine the pressure drop and heat transfer through the heat sink. The results of the heat removal and coefficient of performance (COP) for different types of the grooved microchannel heat sinks are compared to each other as well with those for a simple microchannel heat sink with minimum fin thickness. The comparison shows that the case with minimum vertical fin thickness and arc grooves aligned in 60° on the floor has the maximum heat removal and COP among the studied cases.

Analysis of Pumping Requirements for Microchannel Cooling Systems

2003 ◽  
Author(s):  
Vishal Singhal ◽  
Dong Liu ◽  
Suresh V. Garimella
Keyword(s):  
Heat Sink ◽  
Removal Rate ◽  
Heat Removal ◽  
Critical Factor ◽  
Pressure Head ◽  
Heat Sinks ◽  
Microchannel Heat Sink ◽  
Pressure Drops ◽  
Large Pressure ◽  
Microchannel Cooling

Large pressure drops, and the associated pumping requirements, are often considered the most critical factor hindering widespread commercial use of microchannel heat sinks. Analytical methods are used in the present work to arrive at the pumping requirements for any given microchannel heat sink. A graphical method to check the suitability of a pump to a microchannel heat sink application has been devised. The size of the microchannels is also optimized so that for a specified heat removal rate, the pumping requirements are minimized. A number of commercially available pumps as well as several micropumps presented in the literature are compared based on their flow rate, pressure head and physical size to assess their suitability for a specific representative cooling application.

Stacked Microchannel Heat Sinks for Liquid Cooling of Microelectronic Components

2000 ◽  
Author(s):  
X. Wei ◽  
Y. Joshi
Keyword(s):  
Flow Rate ◽  
Heat Sink ◽  
Water Flow Rate ◽  
Heat Removal ◽  
Single Layer ◽  
Heat Sinks ◽  
Computationally Efficient ◽  
Liquid Cooling ◽  
Number Of Layers ◽  
Microelectronic Components

Abstract A novel heat sink based on a multi-layer stack of liquid cooled microchannels is investigated. For a given pumping power and heat removal capability for the heat sink, the flow rate across a stack of microchannels is lower compared to a single layer of microchannels. Numerical simulations using a computationally efficient multigrid method [1] were carried out to investigate the detailed conjugate transport within the heat sink. The effects of the microchannel aspect ratio and total number of layers on thermal performance were studied for water as coolant. A heat sink of base area 10 mm by 10 mm with a height in the range 1.8 to 4.5 mm (2–5 layers) was considered with water flow rate in the range 0.83×10−6 m3/s (50 ml/min) to 6.67×10−6 m3/s (400 ml/min). The results of the computational simulations were also compared with a simplified thermal resistance network analysis.

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