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.

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.

Performance Comparison of Microchannel Heat Sink Using Boron-Based Ceramic Materials

2021 ◽  
Vol 1163 ◽  
pp. 73-88
Author(s):  
Md Tanbir Sarowar
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Sink ◽  
Electronic Devices ◽  
Ceramic Materials ◽  
Substrate Material ◽  
Heat Sinks ◽  
Maximum Temperature ◽  
Microchannel Heat Sink ◽  
Small Surface

Microchannel heat sink plays a vital role in removing a considerable amount of heat flux from a small surface area from different electronic devices. In recent times, the rapid development of electronic devices requires the improvement of these heat sinks to a greater extent. In this aspect, the selection of appropriate substrate materials of the heat sinks is of vital importance. In this paper, three boron-based ultra-high temperature ceramic materials (ZrB2, TiB2, and HfB2) are compared as a substrate material for the microchannel heat sink using a numerical approach. The fluid flow and heat transfer are analyzed using the finite volume method. The results showed that the maximum temperature of the heat source didn’t exceed 355K at 3.6MWm-2 for any material. The results also indicated HfB2 and TiB2 to be more useful as a substrate material than ZrB2. By applying 3.6 MWm-2 heat flux at the source, the maximum obtained surface heat transfer coefficient was 175.2 KWm-2K-1 in a heat sink having substrate material HfB2.

Experimental Investigation of a PCM-Based Topology Optimized Heat Sink for Passive Cooling of Electronics

2020 ◽  
Author(s):  
Jin Yao Ho ◽  
Kai Choong Leong
Keyword(s):  
Thermal Performance ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Heat Fluxes ◽  
Heat Sinks ◽  
Base Temperature ◽  
Storage Unit ◽  
Cooling Of Electronics

Abstract A thermal energy storage unit filled with phase change material (PCM) can serve as a heat sink for the cooling of electronics with intermittent or periodic heat dissipation rates. The use of thermal conductive structures (TCS) is an effective method of improving the thermal performance of a PCM-based heat sink. In this paper, topology optimization is explored to develop a new class of TCS with a tree-like structure to enhance the thermal performance of a trapezoidal heat sink. The topology-optimized heat sink was then fabricated by Selective Laser Melting (SLM) using an aluminum alloy, AlSi10Mg, as the base powder. Experiments were performed to evaluate the thermal performance of the topology-optimized heat sink with the tree-like structure. In addition, a conventional longitudinal-fin heat sink of the same solid volume fraction (φ = 16.2%) and a heat sink without enhanced structure were also fabricated and experimentally investigated for comparison. Rubitherm RT-35HC paraffin wax was used as the PCM. Three different heat fluxes of 4.00 kW/m2, 5.08 kW/m2 and 7.24 kW/m2 were applied at the base of each specimen by a silicone rubber heater. The structure wall and the PCM temperatures were measured over time. Our results show that, for all heat rates tested, the topology-optimized heat sink was able to maintain a lower base temperature as compared to the fin-structure and the plain heat sinks. A thermal enhancement ratio (ε) is defined to evaluate the performance of the heat sinks with and without the use of PCM. From the experimental results, the highest ε value of 8.6 was achieved by the topology-optimized heat sink. These results indicate the better performance of the topology-optimized heat sink in dissipating heat as compared to the other specimens.

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.

Effect of Flow Arrangements on Thermohydraulic Performance of a Microchannel Heat Sink

2009 ◽  
Author(s):  
Satbir S. Sehgal ◽  
Krishnan Murugesan ◽  
S. K. Mohapatra
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Experimental Studies ◽  
Heat Sinks ◽  
Heat Transfer Analysis ◽  
Maximum Temperature ◽  
Micro Channel ◽  
Flow Conditions ◽  
Micro Channels ◽  
Microchannel Heat Sinks

The advancements in fabricating and utilizing microchannel heat sinks (MCHS) for cooling of electronic devices during the last decade has not been matched by corresponding advances in our fundamental understanding of the unconventional micro fluidics. Many theoretical and experimental studies have been reported for the heat transfer analysis along the direction of flow within the microchannels, but to the best knowledge of the authors, the effect of the size of the inlet and outlet plenum and direction of the flow to the plenums was not studied exhaustively till date. The liquid is supplied to the microchannels via the inlet and outlet plenums and this can be achieved by many flow arrangements. Due to the small size of the channel dimensions, the entrance and exit conditions will significantly affect the heat transfer characteristics of the flow field in the channel. Instability effects at the entrance and exit regions of the micro-channel also need to be fully understood for efficient design of microchannel heat sinks. This paper presents an experimental study that has been conducted to explore the effect of entrance & exit conditions of the liquid flow within a copper micro-channel heat sink (MCHS). Three test pieces having inlet & outlet plenum dimensions of 8mm × 30mm, 10mm × 30 mm and 12 mm × 30 mm each with constant depth of 2.5 mm have been selected. Three different flow arrangements (U-Type, S-type and P-type) are studied for each test piece resulting in total nine flow arrangements. Each micro-channel heat sink contains an array of micro-channels in parallel having individual width of 330μm and channel depth of 2.5 mm. A comparison is made based on thermohydraulic performance of MCHS for different flow conditions at inlet and outlet plenums maintaining constant heat flux. Deionised water has been used in the experiments for the Reynolds number ranging from approximately 220 to 1100. The results are interpreted based on pressure drops and maximum temperature variations for these nine flow arrangements. Tests has been conducted to look for optimized dimensions and flow conditions at inlet and outlet plenums for the given fixed length of microchannels under same conjugate heat transfer conditions. Evaluations of experimental uncertainties have been meticulously made while selecting the instruments used in the experimental facility.

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.

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).

scholarly journals Study of Mini Channel Heat Sink with Different Internal Configuration

2020 ◽  
Vol 319 ◽  
pp. 02004
Author(s):  
Muhammad Akif Rahman ◽  
Md Badrath Tamam ◽  
Md Sadman Faruque ◽  
A.K.M. Monjur Morshed
Keyword(s):  
Nusselt Number ◽  
Thermal Performance ◽  
Heat Sink ◽  
Rectangular Channel ◽  
Three Dimensional ◽  
Heat Sinks ◽  
Maximum Temperature ◽  
Rectangular Channels ◽  
Flow Through ◽  
Internal Configuration

In this paper a numerical analysis of three-dimensional laminar flow through rectangular channel heat sinks of different geometric configuration is presented and a comparison of thermal performance among the heat sinks is discussed. Liquid water was used as coolant in the aluminum made heat sink with a glass cover above it. The aspect ratio (section height to width) of rectangular channels of the mini-channel heat sink was 0.33. A heat flux of 20 W/cm2 was continuously applied at the bottom of the channel with different inlet velocity for Reynold’s number ranging from 150 to 1044. Interconnectors and obstacles at different positions and numbers inside the channel were introduced in order to enhance the thermal performance. These modifications cause secondary flow between the parallel channels and the obstacles disrupt the boundary layer formation of the flow inside the channel which leads to the increase in heat transfer rate. Finally, Nusselt number, overall thermal resistance and maximum temperature of the heat sink were calculated to compare the performances of the modified heat sinks with the conventional mini channel heat sink and it was observed that the heat sink with both interconnectors and obstacles enhanced the thermal performance more significantly than other configurations. A maximum of 36% increase in Nusselt number was observed (for Re =1044).

Relating Semiconductor Heat Sink Local and Non-Local Experimental and Simulation Data to Upper Scale Design Goals

2001 ◽  
Author(s):  
V. S. Travkin
Keyword(s):  
Heat Sink ◽  
Solid Phase ◽  
Physical Characteristics ◽  
Heat Sinks ◽  
Maximum Temperature ◽  
Pin Fin ◽  
Three Samples ◽  
Non Local ◽  
Scale Design ◽  
Research And Design

Abstract The primary difficulty in semiconductor heat sink (and many other types of heat exchangers) research and design is not a lack of interest or money, but rather confusion with what being looked for and adequacy of the tools used for the search. As recently shown, there are few meaningful parameters (apart from sizes and weight) or physical characteristics of interest in semiconductor cooler design are local values. Even the maximum temperature of the base Tmax or semiconductor temperature are not local. In this work outlined the description in detail of arguments on how, and for what reasons, the measured data are to be simulated or measured and represented in a way that allows design goals to be formulated primarily with bulk physical characteristics. We demonstrate why studies of only averaged local integrated variables are not enough. Four sample semiconductor heat sinks of two morphologies (three samples of round pin fin and one sample of longitudinal rib fin sinks) were studied by different techniques and models. There were changes in by-pass values, external heat flux and flow rate. The results are depicted with using new parameters that better represent the needs of a design process as well as the usual parameters used in the past. Characteristics reported are the heat transfer rate in solid phase, relative fin effectiveness, and influence of only morphology features among others. Some suggestions for heat sink design are discussed.

Sign in / Sign up

Export Citation Format

Share Document