Thermal Performance Of Heat Sink Research Articles

Computational analysis of microchannel heat sinks with constant circular pin fins: Performance evaluation and optimization

This research entails a comprehensive computational simulation aimed at comparing the performance of microchannel heat sinks (MCHS) featuring 55-pin fins, characterized by constant circular pins with a diameter of 15µm, uniform spacing of 50µm, and variable heights ranging from 60 to 35µm. The primary objective was to assess the performance of these models with a reference Mini channel. Mesh independence validation was meticulously executed on MCHS with pin fins to ascertain the accuracy of the computational findings. The simulation encompassed seven Reynolds numbers within the range of 500–1500. The performance evaluation incorporated hydraulic and thermal factors, specifically pressure drop, Nusselt number, and the thermal performance factor (TPF). A holistic assessment of overall performance was achieved through the establishment of a heat sink thermal performance factor, accounting for both hydraulic and thermal aspects. The optimal geometry was determined based on this factor, and corresponding visual representations were generated to illustrate these findings.

A Novel Plate Fin Heat Sink Design With Rectangular Slots and Interruptions: A Computational Approach

Abstract In the present work, we have studied the performance of vertical plate finned heat sinks that protrude from a vertical base. The difference between the heat sink base temperature and the ambient, i.e., ΔT, has been varied in the range of 10 °C to 60 °C, and the flow undergoes a natural convection regime. To enhance the thermal performance, we have explored different configurations of the heat sink by providing rectangular slots, varying the neck thickness, changing the neck location from the fin base, and providing interruptions along the fin height. The pertinent quantities, i.e., heat dissipation rate, Nusselt number, effectiveness, mass of heat sink, and heat dissipation per unit mass, have been obtained by performing 3D computational simulations. The results obtained are compared to assess the thermal performance of heat sinks. We found that among various designs of heat sinks proposed, the heat sink with two slots, with the location of neck closer to the fin base (xm = 9 mm), and with interrupted fins dissipates maximum heat (12.86% more compared to the commonly used rectangular plate finned heat sink). In addition to the heat transfer improvement, 19.82% mass reduction has also been achieved. Based on the simulation data, we have proposed a correlation for the mean Nusselt number as a function of relevant non-dimensional parameters.

Multi-objective optimization of a porous diverter plate for a liquid-cooled micro-jet heat sink via surrogate modeling

This work reports on the optimization of a porous diverter plate for a micro-jet heat sink to obtain the optimum jet nozzle diameter and flow opening ratio, which play a significant role in the cooling characteristics of heat sinks for electronic chips. An artificial neural network (ANN) model was used to optimize and predict the sensitivity of different parameters (coolant flow rate, opening ratio, and jet nozzle diameter) on the operation of the heat sink design. It was found that smaller opening ratios and jet nozzle diameters in the range of 2.0–3.2 mm had a positive effect on improving the heat sink's thermal performance. Moreover, the diverter plate's opening ratio had a major sensitivity to pumping power, while the jet nozzle diameter had the lowest sensitivity. Finally, the overall cooling characteristics of all the designs were evaluated using the PPTR parameter, and the results demonstrate that the porous diverter plate with an opening ratio of 0.08 and a jet nozzle diameter of 1.81 mm yielded the optimum design for the porous diverter plate of the heat sink.

Investigation on the thermal control and performance of PCM–porous media-integrated heat sink systems: Deep neural network modelling employing experimental correlations

Phase change material (PCM)-based heat sinks can offer reliable and effective thermal management (TM) solutions for increasingly sophisticated applications. A critical aspect of such heat sinks is determining how long it takes them to reach a set-point temperature. However, no generalised method exists in the literature that can predict and interpret the thermal performance of a wide range of PCM–porous media-integrated heat sinks. In this regard, this study examines the heat transfer characteristics of PCM-based heat sinks integrated with various metallic foams through experimental and deep learning (DL) techniques. The experiments are performed for transient TM analysis of various PCM-based heat sinks. Diverse variables, including foam porosity (0.95–0.97), PCM fraction (0.6–0.8), heat flux (0.8–2.4 kW/m2), foam materials (Fe–Ni alloy, Ni and copper) and PCM type (RT-35HC, RT-44HC, RT-54HC and paraffin wax), are investigated in this study. The experimental data are fed to the optimal DL model using the Bayesian surrogate model-tuned hyperparameters. Utilising a correlation analysis, as exemplified by the heat map and correlation plot, in conjunction with explainable artificial intelligence, it has been deduced that the thermal performance of the heat sink is principally influenced by factors such as PCM type, PCM fraction, foam material, foam porosity, and heat flux. Comparing the model's predicted data with the empirical findings, a good agreement was observed. Specifically, the mean absolute error (MAE) for the anticipated temperature and gradient registered at 0.0438 and 0.0054, whilst the mean square error (MSE) manifested values of 0.0579 and 0.0087, respectively. The proposed model can accurately assess the heat sink's thermal performance (correlation coefficient, R2 = 0.99) for various PCM types, fractions, foam materials, applied heat flux and foam porosity.

Thermal performance of microchannel heat sink integrated with porous medium, slip coefficient and phase change material and machine learning approach

In this study, the thermal performance (TP) of the microchannel heat sink (MCHS) under the influence of the slip coefficient on the microchannel wall, the use of porous medium (PM) and phase change material (PCM), and the changes in the geometrical parameters and the shape of the microchannel have been discussed. The flow and energy equations were solved using the finite volume method. The validation of the melting process, slip coefficient, and porous medium with the previous literature demonstrate the high accuracy of the numerical solution, with the difference between the results being <8 %. The results indicate that using a wavy microchannel can improve TP by approximately10.6 % and 5 % compared to smooth and converging microchannels. Additionally, using non-Newtonian fluids with a power characteristic of 0.53 leads to improved TP about 2.8 % by reducing shear stress compared to Newtonian fluids. Furthermore, the presence of slip on the microchannel wall influences the flow pattern, resulting in reduced convection resistance and improved TP about 3.2–3.8 %. The highest TP was observed at a slip coefficient of 0.00001. Incorporating PM in the microchannel (either in the center or around it) can enhance TP by approximately 8–15 % compared to the base state, with greater improvements observed when PM is placed around the microchannel. The type of PM material and the porosity coefficient significantly impact TP. Varying the cross-sectional shape of the microchannel (square, rhombus, and triangle) has a substantial effect on improving TP compared to a circular cross-section, with the highest TP (with a 71 % increase) observed in microchannels with a square cross-section. Lastly, the use of PCM and PM on the active surface leads to a significant TP improvement of over 80 % compared to the base state. Using the Group Method of Data Handling algorithm, thermal resistance was estimated with an R-square value of 0.94 to validate the available data.

Natural convection heat transfer in a three-dimensional enclosure under the effect of heated pin-fins of various shapes

Natural convection enhancement for heat sinks with the help of pin-fins has been extensively researched, but further investigations are still required regarding the technological development. In order to understand the effect of different pin-fins shapes on the heat transfer and fluid flow pattern in a three-dimensional air-filled enclosure, a numerical investigation is conducted. The enclosure is heated by the left wall, on which pin-fins are attached, and cooled by the right wall, while the other walls are considered adiabatic. A validation has been made with both experimental and numerical results from the literature, and a good agreement has been observed. Five pin-fins shapes with the same base surface area and length are tested: circular, triangular, square, pentagonal, and hexagonal. The findings show that the circular pin-fins exhibit the highest thermal performance. Furthermore, for different Rayleigh numbers, increasing the number of pin-fins improves the thermal performance of heat sinks.

Dynamic regulation of the thermal performance of the S–CO2 minichannel using a piezoelectric oscillating fin

It is difficult to alter the thermal performance of a minichannel heat sink with a fixed structure under constant operating conditions. In particular, if the local heat transfer of the substrate cannot be regulated in real time, the dynamic heat dissipation needs of high-power electronic components cannot be met in the electrical servo systems of flight vehicles. In this paper, a new minichannel heat sink structure based on the classical rectangular channel is proposed and a piezoelectric oscillating fin (POF) is introduced to replace the fixed fin. The thermal performance of the heat sink can then be regulated using the swing of the POF, with supercritical carbon dioxide (S–CO2) as the coolant. Transient numerical simulations are applied to investigate the influence of various POF operating parameters on the heat transfer of the channel, such as the oscillation amplitude and frequency. The results demonstrate that a channel with a POF can allow for dynamic and rapid adjustment of the thermal performance through control of the oscillation frequency and amplitude of the POF, with a constant channel configuration, coolant, and operating conditions. The heat transfer can be enhanced significantly by the swing of the POF, with the local Nusselt number growing up to 8.3 times and the overall one up to 1.14 times. Both the oscillation frequency and amplitude have a positive correlation with the intensity of heat transfer. The POF also contributes to a greater pressure drop and fluctuation in pumping power. A comprehensive evaluation coefficient shows that the POF is effective at improving the overall thermal performance with a low-frequency swing, while high-frequency operation enhances the local heat transfer and decreases the local temperature near the tail end of the POF. Finally, considering the effects of the frequency and amplitude of the POF, as well as the variable thermophysical properties of the supercritical coolant, a heat transfer correlation based on the Dittus–Boelter equation is established to predict the thermal performance of the channel with a POF. This prediction has a maximum error of ±0.56%.

Thermal analysis and optimization of metal foam PCM-based heat sink for thermal management of electronic devices

Efficient thermal management in electric devices is highly essential for ensuring the reliability and durability of electronics. This study aims to investigate the thermal performance and optimization of metal foam PCM-based heat sink for thermal management units. Different design parameters, such as PCM types (RT31, RT42, and RT55), metal foam porosities (85%, 90%, and 95%), and metal foam materials, are studied to determine heat sink optimal parameters, considering various critical temperatures: 40 °C, 50 °C, 60 °C and 70 °C. The volume-averaged method is used to simulate the heat transfer, phase change, and fluid flow within the heat sink unit. Heat transfer between PCM and metal foam is established using a thermal non-equilibrium model. The results show that the usage of metal foam is conducive to the thermal performance enhancement of heat sinks. Among the three parameters, PCM types show a considerable effect on thermal performance of heat sinks, e.g., the maximum operation time of heat sinks with RT31 is about 5 times that of heat sinks with RT55 for the critical temperature of 40 °C. Among all the cases, heat sinks using RT31 and aluminum foam perform optimally, which can achieve the optimal design of heat sinks.

An experimental and numerical comparison study on a heat sink thermal performance with new fin configuration under mixed convective conditions

The heat sinks thermal performance with four aluminum fin configurations set under mixed convection settings at three voltage values 100, 150, and 200 V, was examined. Six fins are part of a heat sink. The flat fin is the first type (case1), the corrugated fin was the second (case2), the third one was a corrugated fin with rectangular perforations with its rib (case3), and the last one was corrugated with triangle perforations with its rib (case 4). The surface area of all studied cases is equal. The third and fourth studied cases are new proposed configurations by this work. The air velocity was 1.5 m/s. The temperature distribution along the fin surface was measured for each case study. The theoretical study was held on each studied case using a fluent package (ANSYS18 software). The absolute deviation between the experimental and numerical study for each studied case temperature distribution is 2.95% for case 1, 3.37% for case 2, 1.41% for case3 and, and 1.2% for case 4 at 160 W supplied power heater. Cases (3 and 4) will enhance the heat transfer coefficient compared to the flat fin case 11) which was 4.16% and 4.27% respectively. The fin perforations with its ribs case (3 and 4) decrease the material cost and heat sink weight to 7.7% and 8.3% respectively. Also, the required space to locate the heat sink is minimized

Thermal performance of open microchannel heat sink with NACA airfoil shaped pin fins

ABSTRACT The main purpose of this study is to numerically investigate the effect of pin-fin National Advisory Committee for Aeronautics (NACA) airfoil on the heat transfer performance of a single open microchannel heat sink with a fixed surface area and a constant wall heat flux. It was found that the helical flow within the microchannel and the converging–diverging flow near the two sides of the microchannel, caused by the periodically arranged NACA airfoil shaped pin fins with an attack angle, dominate the overall heat dissipation ability of the heat sink. The heat dissipation ability can be further improved by increasing the attack angle and Reynolds number. Of the airfoils considered, the symmetrical airfoil NACA0012 in no attack angle case presents the smallest pressure drop, but also the smallest thermal performance value, which can still achieve a Nusselt number improvement of 35.15% and a thermal performance factor (TPF) improvement of 1.38%, compared to the no-fin case. The NACA airfoil effect can be improved when asymmetric airfoils are considered. In terms of overall thermal performance, the NACA6412 would be the best choice. Its percentage increases in the Nusselt number and TPF can be further enhanced by up to 57.62% and 35.43%, respectively, compared to the no-attack-angle NACA0012 case.

不同直径和流量对层叠式微通道散热器热性能的影响研究

不同直径和流量对层叠式微通道散热器热性能的影响研究

Server processor heat sink analysis and modifications to improve its thermal performance

Heat generation in the electronic components of high-performance computing servers is a matter of concern. Heat generation adversely affects the performance of these servers, certain temperature limits are required for these server processors and other electronic components to work within suitable conditions. Furthermore, in order to improve CPU performance and functioning, the heat flux in today's processor packages is increasing day by day, even as server CPUs and other components shrink in size. The air-cooling technique is the most broadly utilized and efficient technique of the present accessible electronic cooling advances. In data centers, heat sinks with forced air are utilized to keep server processors and other electronic components cool. The cooling systems of electronic gadgets are a growing field of research. The aim of this work is to contribute to this research field by investigating the effects of inlet air properties on server processor heat sink thermal performance with a heat load of 140 W. The heat sink performance depends on various parameters. The influence of various geometries of lateral perforation on heat sink fin walls was numerically analysed in this study to improve the thermal performance of the server processor plate fin heat sink. The CFD Solver is used for analysing the performance of heat sink and the effect of lateral perforation shapes on heat sink fins. The three shapes of perforation are considered as square, circular, and hexagonal types, with the same cross-sectional area and pitch of inline arrangement. In comparison to plate fin heat sinks, the numerical results demonstrate that a laterally perforated finned heat sink has a lower base temperature and a low thermal resistance. The use of a perforated heat sink also saves material and reduces the weight of the heat sink.

Numerical Analysis of the Thermal Performance of a PCM-Based Heat Sink Under Flight Random Vibration

Numerical Analysis of the Thermal Performance of a PCM-Based Heat Sink Under Flight Random Vibration

Experimental Study of Thermal and Pressure Performance of Porous Heat Sink Subjected to Al2O3-H2O Nanofluid

With the developing technology, the dimensions of electronic systems are becoming smaller, and their performance and the amount of energy they need increases. This situation causes the electronic components to heat up more and the existing cooling systems to become inadequate. In this study, instead of the fins used in existing systems, 10 PPI and 40 PPI PHS were placed inside a water block, and the Al2O3-H2O nanofluid at a mass fraction of 0.1% was used as the cooling fluid. Experiments were carried out under constant heat flux of 454.54 W/m2 and 1818.18 W/m2, with volumetric flow rates varying between 100 mL/min and 800 mL/min. The heat transfer results were compared with the results obtained from the base fluid and the empty surface. The results showed that the nanofluid reduced the surface temperatures compared to the base fluid. Especially when PHSs were used together with the nanofluid, a significant increase in heat transfer occurred compared to the empty surface. The highest heat transfer was observed when both the nanofluid and 40 PPI PHS were used together. In addition, the highest thermal performance value was determined as 1.25 times compared to the empty surface when the nanofluid and 10 PPI PHS were used together.

Thermal and hydraulic performance of solid-porous compound wavy micro-channel heat sinks

In this numerical study, seven distinct three-dimensional unique models of micro-channel heat sinks have been investigated. A solid-porous compound wavy channel with optimum thickness of porous fins has been newly adapted to improve the thermal and hydraulic performance of the forthcoming micro-electronic devices. The finite volume method is used to solve the hydraulic and thermal performance of micro-channel heat sinks, and Darcy–Forchheimer flow models are applied for fluid flow through porous fins. Water is employed as a working fluid. Solid wall and porous fins are made of copper material; during analysis, Reynolds numbers vary from 50 to 300, and the effective thermal conductivity has been considered for porous fins as well as solid-porous compound fins. The effect of solid fins, porous fins, and compound fins are comprehensively determined. The result shows that as the thickness of porous fins increases in compound wavy channel, the heat transfer performance significantly increases up to 63.6% and pressure drop penalty decreases up to 55.32% as compared to the regular straight channel (solid fins) heat sinks. This is due to reduction of viscous shear stress at the place of fluid-porous interface and slip effect of fluids in the porous zone. Hence, the ability of the solid-porous compound wavy micro-channel heat sinks can effectively enhance the cooling performance of high-power electronic devices.

Using a Multi-Inlet/Outlet Manifold to Improve Heat Transfer and Flow Distribution of a Pin Fin Heat Sink

Abstract The increased power consumption and continued miniaturization of high-powered electronic components have presented many challenges to their thermal management. To improve the efficiency and reliability of these devices, the high amount of heat that they generate must be properly removed. In this paper, a three-dimensional numerical model has been developed and experimentally validated for several manifold heat sink designs. The goal was to enhance the heat sink's thermal performance while reducing the required pumping power by lowering the pressure drop across the heat sink. The considered designs were benchmarked to a commercially available heat sink in terms of their thermal and hydraulic performances. The proposed manifolds were designed to distribute fluid through alternating inlet and outlet branched internal channels. It was found that using the manifold design with 3 channels reduced the thermal resistance from 0.061 to 0.054 °C/W with a pressure drop reduction of 0.77 kPa from the commercial cold plate. A geometric parametric study was performed to investigate the effect of the manifold's internal channel width on the thermohydraulic performance of the proposed designs. It was found that the thermal resistance decreased as the manifold's channel width decreased, up until a certain width value, below which the thermal resistance started to increase while maintaining low-pressure drop values. Where the thermal resistance significantly decreased in the 7 channels design by 16.4% and maintained a lower pressure drop value below 0.6 kPa.

Thermal management of 18650 Li-ion battery using novel fins–PCM–EG composite heat sinks

The present study introduces a novel fin–Phase Change Material (PCM)–Expanded Graphite (EG) composite for better thermal management of a Panasonic NCR18650BD battery at discharge rates higher than its maximum discharge limit 2C. Fins and EG are augmented with PCM to enhance its effective thermal conductivity. Initially, the electrical and thermal behaviors of the battery are simulated for 0.5, 1, and 2C discharge rates using the Newman P2D model, and these are validated against in-house experiments. Following this, the heat generation profiles are estimated from the numerical model to mimic the battery with a heater in the experiments conducted to propose an effective thermal management system for 2, 3, and 4C discharge rates. Three heat sinks, one sans fins, and the other two with 130 and 260 fins, respectively, are considered to perform experiments. Phase Change Material (PCM) named Eicosane (Ei) with an addition of 0, 10, 20, 25, and 30% weight fractions of EG is filled in the heat sinks to study the effect of composite PCM on the thermal regulation of the battery. The heat sink having 260 fins filled with 70% Ei - 30% EG composite outperforms the other heat sinks considered in this study by recording lower temperatures to the extent of 17.5, 20.5, and 22.7 °C than a plain heat sink filled with 100% Eicosane for discharge rates 2, 3, and 4C, respectively. Furthermore, with the addition of 30% EG by volume, the maximum thermal performance of heat sink having 130 fins surpasses the heat sink having 260 fins filled with pure Eicosane by recording 1.3, 0.5, and 1.5 °C lower temperatures for discharge rates 2, 3, and 4C, respectively. In view of this, a possible engineering solution is to employ a simple heat sink, having fewer fins filled with PCM–EG composite instead of intricate heat sinks, having more fins filled only with the baseline PCM, to overcome the design difficulties and manufacturing costs.

Effect of diamond microparticles on the thermal behavior of low melting point metal: An experimental and numerical study

Low melting point metal (LMPM) based composite containing particles with high thermal conductivity has potential application prospects in the field of thermal management. To investigate the influence of particles with high thermal conductivity on the thermal behavior of LMPM during its melting/solidification process, lead free eutectic field's metal Bi32.5In51Sn16.5 was selected as the LMPM and diamond microparticles were used as the thermal conductive reinforcement. The thermal conductivity of the LMPM increased 85% as the mass fraction of diamond particles was 4.7%. Thermal performance of LMPM-based heat sink influenced by diamond particles was studied. Compared with the LMPM-based heat sink, heating element using heat sink filled with LMPM/diamond composites maintained a lower temperature during long-time heating and cooled faster as its power-off. The effect of diamond particles on the melting/solidification process of LMPM was investigated. The melting duration of LMPM was prolonged by adding diamond particles. After LMPM was compounded with diamond, the subcooling existing in LMPM was reduced and its initial solidification time was shortened. The thermal performance of LMPM/diamond-based heat sink showed more stability than that of LMPM-based heat sink during the heating/cooling cyclic tests. Meantime, the relative position of diamond particles in LMPM was basically immobile through 1000 melting/solidification cyclic tests.

Oriented square shaped pin-fin heat sink: Performance evaluation employing mixture based on ethylene glycol/water graphene oxide nanofluid

Based on effective heat dissipation in electronic devices, the current study deals with heat transfer characteristics of oriented square shaped pin fin heat sink having a fin angle of 22.5°. It has been investigated experimentally employing graphene oxide (GO) nanofluid under laminar flow regime. The performance of graphene oxide (GO) nanofluid having concentrations of 0.004%, 0.0065%, and 0.009 vol% is compared with a mixture of EG-water (50:50) as base fluid under three different heating powers of 20 W, 35 W, and 50 W. The experimental results revealed better thermal performance for all used concentrations of (GO) nanofluid compared to the base fluid due to the heat transfer augmentation and reduction in thermal resistance as a result of enhanced thermal conductivity of nanofluid. It was observed that the thermal performance of heat sink improved with increasing Reynolds number and heating power. Minimum wall temperature and maximum enhancement in Nusselt number of 30.75 °C and 19.68% respectively is associated with graphene oxide nanofluid having a concentration of 0.009 vol%. According to the results, nanofluid exhibited better trends of thermal enhancement in comparison of EG/water base fluid with an increase in nanoparticle concentration usually at low Reynolds number. Thus, graphene oxide nanofluid has proven to be the potential candidate for improving the thermal performance of heat sink.

Experimental and numerical investigation on thermal and hydraulic performance of novel serpentine minichannel heat sink for liquid CPU cooling

A novel serpentine design for minichannel heat sink is investigated experimentally and numerically to enhance thermal performance of the heat sink for liquid CPU cooling. The heat sink is fabricated from aluminum and is located in a plexiglass container. The channels have square cross section with deep and width of 2 mm. Mass flow rate and inlet temperature effect on the performance of the maze serpentine heat sink are studied. Five different mass flow rate varies between 0.0017 kg/s and 0.0087 kg/s and three different inlet temperature (15°C, 20°C and 25 °C) is investigated. Pure water is used as the coolant. The results indicate that by changing the minichannel design from straight to the proposed mazed shape geometry, baseplate temperature decreases 11.2% and Nusselt number increases 4.2 times in the maximum mass flow rate. Thermal resistance is decreased in the novel maze serpentine minichannel heat sink and by increasing mass flow rate the difference get larger so that maximum convective thermal resistance difference for and the novel maze serpentine minichannel is 54% that is observed in the lowest mass flow rate. Also, higher thermal performance is achieved in the maze serpentine minichannel heat sink.