Performance Of Heat Sink Research Articles

Performance enhancement in minichannel heat sinks using supercritical carbon dioxide (sCO2) as a coolant

Minichannel heat sinks are widely adopted heat dissipation solutions from miniaturized heat flux generating components, such as microprocessors. This paper presents further enhancements in the thermal and hydraulic performance of a minichannel heat sink by employing supercritical carbon dioxide (sCO2) as a coolant. In this study, thermal and hydraulic performance of CO2-cooled minichannel heat sink at three inlet pressures (Pin,CO2) (i.e., 8.0, 10 and 12 MPa)and inlet temperatures (Tin,CO2) ranging between 30∘C−60∘C is compared with a water-cooled minichannel heat sink at inlet conditions (0.1 MPa,30 °C−38 °C). To investigate the performance of the minichannel heat sinks, a conjugate heat transfer model is solved in a commercial code ANSYS-CFX. Whereas the variations in thermo-physical properties of supercritical carbon dioxide (sCO2) are incorporated in ANSYS-CFX through a real gas property (RGP) table. The results reveal a maximum enhancement of 42.13% in average heat transfer coefficient (h¯) for minichannel heat sink using CO2 as a coolant at inlet conditions of 8.0 MPa and34∘C. Similarly, a pressure drop reduction of 55.79% is computed for CO2 as a coolant at corresponding inlet conditions as compared to water-cooled minichannel heat sink. Moreover, the results suggest that replacing water with CO2 as a coolant at higher inlet pressures (Pin,CO2) i.e., 10 MPa and 12 MPacan further reduce pressure drops in the minichannel heat sink by 60.65% and 62.41%, respectively. Apart from the lower base temperatures, performance evaluation criteria (PEC) suggests that the overall performance of the minichannel heat sink using CO2 at 8.0 MPa is roughly enhanced by 2 times as compared to water-cooled minichannel heat sink.

Heat-dissipation performance of cylindrical heat sink with perforated fins

The temperature of light-emitting diode (LED) light bulbs must be managed to maintain their performance and increase their lifespan, and the design and application of an appropriate LED heat sink are particularly important for temperature management. This study investigated the heat-dissipation performance of a heat sink with perforated fins on a cylindrical base. To improve the heat-dissipation performance of the heat sink, the effects of the size and number of perforations per fin were examined. A larger number of perforations with a smaller size were found to be favorable for the improvement of the heat-dissipation performance. Both the size and number of perforations, however, had threshold values for lowering the thermal resistance. Moreover, the heat-dissipation performance was numerically analyzed according to the Rayleigh number, number of fins, fin inclination angle, and orientation angle of the heat sink. In addition, the numerical analysis method used was experimentally verified. As the number of fins increased, the thermal resistance decreased because of the corresponding increase in the heat-dissipation area of the heat sink. Furthermore, the thermal resistance was found to vary with respect to the fin inclination angle, making it possible to reduce the degradation of the heat-dissipation performance by varying the orientation angle. On this basis, a correlation was derived for predicting the thermal resistance of the cylindrical heat sink with perforated fins. The derived correlation accurately predicted the thermal resistance within a maximum error of 5.25%.

CFD simulation of the impact of tip clearance on the hydrothermal performance and entropy generation of a water-cooled pin-fin heat sink

In this paper, the 3D numerical calculations of the water flow inside a pin-fin heat sink (PFHS) to determine the influence of tip clearance on the hydrothermal behavior and frictional & thermal irreversibilities of the fluid flow. The numerical simulations were conducted for five different fin heights (ξ = 1.5 mm to 2.5 mm) considering four different Reynolds numbers (Re=500, 1000, 1500, and 2000). The results demonstrated that the highest heat transfer coefficient is associated with ξ = 2.25 mm due to more uniform vorticity distributions, while the minimum central processing unit (CPU) average temperature is obtained for ξ = 2.5 mm due to the higher heat transfer surface area. The minimum thermal and frictional entropy generation rates are associated with PFHS with ξ = 1.5 mm. However, the PFHS with ξ = 2.25 mm has the highest Performance Evaluation Criterion (PEC) of nearly equal to 1.28 as compared to the other ξs. Besides, the fluid flow from the pin-fin base to the top and vice versa leads to create the vortices especially at the entrance of the PFHSs with tip clearance.

Thermo-hydraulic performance of modified plate fin and pin fin heat sinks

Extended surfaces are widely investigated for their ability to enhance the heat transfer rates in different applications. Pin-fin and plate-fin heat sinks are used in a variety of cases involving a miniaturized to the large systems. The present study compares the performance of the pin-fin and the plate-fin heat sink under similar forced flow conditions. The experimental data for a modified pin fin heat sink with wings and a plate-fin heat sink with dimples are collected for the Reynolds number in the range of 6800–15100. The Nusselt number, friction factor, and thermo-hydraulic performance (THP) are examined for different geometries of the heat sink and the enhancements brought out in the heat transfer and friction are gauged relative to the smooth plate. The pin fin heat sink yields two-fold enhancement in heat transfer as compared to the plate-fin heat sink. The maximum thermo-hydraulic performance of the pin-fin heat sink with wings is found to be 4.52 at a pitch ratio (S/Df) of 2 and Wing length ratio (Lw/Df). For the plate fin heat sink with dimples, the maximum thermo-hydraulic performance is found to be 4.67 at dimple diameter ratio (D/d) of 0.5 and dimple pitch ratio (s/d) of 2.5. The correlations of the Nusselt number and friction factor are proposed for different geometries of fins.

Heat Dissipation Performance of Micro-channel Heat Sink with Various Protrusion Designs

This research will focus on studying the effect of aperture size and shape of the micro-channel heat sink on heat dissipation performance for chip cooling. The micro-channel heat sink is considered to be a porous medium with fluid subject inter-facial convection. Derivation based on energy equation gives a set of governing partial differential equations describing the heat transfer through the micro-channels. Numerical simulation, including steady-state thermal analysis based on CFD software, is used to create a finite element solver to tackle the derived partial differential equations with properly defined boundary conditions related to temperature. After simulating three types of heat sinks with various protrusion designs including micro-channels fins, curly micro-channels fins, and Micro-pin fins, the result shows that the heat sink with the maximum contact area per unit volume will have the best heat dissipation performance, we will interpret the result by using the volume averaging theorem on the porous medium model of the heat sink.

Numerical investigation on the influence of installation angle of inclined interrupted fins heat sink on heat dissipation performance

Numerical simulations of a symmetric array of inclined fins heat sink under natural convection had been carried out using the ANSYS icepak to solve the complete Navier-Stokes equation and the energy equation in the current study. The effects of fin height (20 mm ≤ H ≤ 40 mm) and heat sink installation angle (–45° ≤ φ ≤ 30°) were analyzed. The work fluid was the air. The results showed that when the input power was constant, as the fin height increased, the heat transfer performance improved. There was no better heat transfer performance than the case of fin height was 40 mm, of which the corresponding heat transfer resistance was also almost the lowest. Compared with H = 20 mm and H = 30 mm, the case of H = 40 mm can reduce the average substrate temperature by 5%−10%. The installation angle greatly affected the heat transfer performance of the heat sink. Compared with the negative installation angle, the positive installation angle showed stronger inhibition on the heat dissipation. The installation angle of −15° showed the highest heat transfer coefficient, which could improve the heat transfer coefficient by about 7%. The Nusselt number (Nu) was found to increase approximately linearly with the Rayleigh number (Ra) in the range of 8.5 × 106 ∼ 1.64 × 107. A correlation between Nu and Ra, the geometric parameters of fin arrangement and the dimensionless correlations related to the heat sink installation angle were obtained. Highlights A new type of fin heat sink was proposed to improve heat sink performance. The heat sink installation angles was studied with the best angle found. The correlation formula related to the installation angle was obtained.

Effects of surfactant and nanofluid on the performance and optimization of a microchannel heat sink

This paper reports the influence of surfactant Triton X-100 on boron nitride nanotubes (BNNTs) nanofluid in non-optimized and optimized microchannel heat sink (MCHS) at 30 °C and 50 °C. The MCHS performance was evaluated in terms of thermal resistance and pressure drop, utilizing experimental thermophysical properties of distilled water, a mixture of distilled water and surfactant Triton X-100 as base fluid, and nanofluid BNNTs at weight concentration of 0.001% into MCHS models which was further optimized with the Multiple Objective Particle Swarm Optimization (MOPSO) technique. It is found that the surfactant at 30 °C improves the MCHS thermal capabilities without nanotubes by 0.8% even after optimizing the MCHS according to the fluid properties. Conversely, surfactant Triton X-100 reduces pressure drop greatly with any change in thermal resistance at 50 °C and paired cooperatively with BNNTs nanofluid 0.001wt.% - mitigating pressure drop increment caused by the nanofluid resulting an overall performance improvement by 1.25% and 1.97% for thermal resistance and pressure drop respectively in MCHS systems and reduced to 1.3% and 3.2% after optimization. Optimized MCHS dimensions given by MOPSO could be manufactured and additionally gave wider solutions for large reduction of pressure drop up to 80% for economic MCHS with a drawback of higher thermal resistance.

An artificial neural network model for predicting frictional pressure drop in micro-pin fin heat sink

Abstract This study is part of two studies conducted for developing artificial neural-network-based tools for predicting the thermal and hydraulic performance of micro-pin fin heat sinks used for high-heat-flux electronic devices. The thermal design of high-heat-flux electronics requires a strong understanding of both pressure drop and heat transfer coefficient. Increasing the pressure drop in a cooling system significantly increases the required pumping power and decreases the system energy efficiency, in addition to considerably increasing temperature nonuniformity and causing reliability issues. Micro-pin fin heat sinks can help in the thermal management of high-heat-flux electronic systems owing to their effective heat transfer characteristics, namely, a large surface area and passage flow turbulence generation, and the requirement of lower pumping power compared with the microchannel heat sink. Studies conducted over the past decade have revealed that the thermal and hydraulic performance of micro-pin fin heat sinks are highly dependent on their geometric and operational parameters. However, a universal approach to predicting the frictional pressure drop, which influences the amount of power required, in pin fin arrays for various operating conditions and geometric shapes has not been developed so far. In this study, a trained artificial neural network (ANN) was used to develop a universal model for predicting the friction factor of micro-pin fin arrays. The friction factor correlation was predicted from 1,651 experimentally determined friction factor data points obtained from 22 studies. The relationship between a wide range of geometric and operating conditions and the hydraulic performance was investigated for accurately training the ANN. Furthermore, the universal model was analyzed by comparing values predicted by it with values obtained in other experimental studies. The model was found to show superior performance compared with other regression-method-based correlations.

Thermal performance of heat sink using nano-enhanced phase change material (NePCM) for cooling of electronic components

Present experimental study reports the thermal performance of nano-enhanced phase change material (NePCM) based thermal energy storage system for cooling of electronic components. The NePCM based heat sink (HS) cooling is a passive cooling technique that can eliminate the fan-based conventional cooling technique. A plate heater was used to impersonate the heat generated by microelectronics. Here, copper oxide (CuO), paraffin wax, and aluminum are considered as nanoparticle, phase change material (PCM), and HS material, respectively. Different HS configurations such as HS with no fin (HSNF), HS with rectangular plate fins (HSRPF), HS with square pin fins (HSSPF), and HS with circular pin fins (HSCPF) are studied for a fixed volume fraction of fin material. The performance of various HS configurations are analyzed for different nanoparticle concentration (∅=0.5–3.0), and heat flux values (q′′=1.5–3.0 kW/m2). For ∅= 3.0, thermal conductivity and viscosity of NePCM are found to increase by 150% and 100%, respectively. The HSSPF involving PCM/NePCM exhibits better thermal performance compared to other HS configurations. The maximum reduction in temperature is found to be 13 °C and 15 °C for HSSPF involving PCM and NePCM (∅= 0.5), respectively. The highest enhancement ratio of 5.0 is obtained for HSSPF at q″= 2.0 kW/m2 for SPT of 65 °C. The addition of CuO nanoparticle beyond ∅=0.5 decreases the HS performance considerably.

Uncertainty quantification of heat transfer in a microchannel heat sink with random surface roughness

To numerically investigate the stochastic heat transfer performance of a microchannel heat sink, a randomly generated, rough surface profile with a prespecified autocorrelation function is applied to its bottom surface. The magnitude of the maximum relative roughness of the surface is treated as a Gaussian random input with specified uncertainty, and uncertainty in the output is modeled via polynomial chaos expansions. According to deterministic analysis of the simulation results, an increase in surface roughness enhances the heat transfer. As found through stochastic analysis of the joint probability density functions of the local surface height and local Nusselt number, the local surface height alone is insufficient to explain changes in the local Nusselt number, and the sensitivity of the local Nusselt number to other factors increases with the absolute value of the local surface height. Polynomial chaos expansions are used to identify the peaks and ridges of the surface as regions where the Nusselt number and velocity magnitude are more sensitive to the local surface roughness than in valleys. Probability density functions are estimated from the polynomial chaos expansions of the local Nusselt number, spanwise-averaged Nusselt number, and three global outputs: the average Nusselt number over the rough bottom surface, the pressure drop over the channel, and the performance factor of the bottom surface. Because of nonlinear propagation of the Gaussian random input, the distributions of the local and spanwise-averaged Nusselt numbers can not generally be assumed to have a Gaussian shape. In contrast, the global outputs can be treated as Gaussian as a good approximation.

Evaluation of Active Heat Sinks Design under Forced Convection-Effect of Geometric and Boundary Parameters.

This study shows the performance of heat sinks (HS) with different designs under forced convection, varying geometric and boundary parameters, via computational fluid dynamics simulations. Initially, a complete and detailed analysis of the thermal performance of various conventional HS designs was taken. Afterwards, HS designs were modified following some additive manufacturing approaches. The HS performance was compared by measuring their temperatures and pressure drop after 15 s. Smaller diameters/thicknesses and larger fins/pins spacing provided better results. For fins HS, the use of radial fins, with an inverted trapezoidal shape and with larger holes was advantageous. Regarding pins HS, the best option contemplated circular pins in combination with frontal holes in their structure. Additionally, lattice HS, only possible to be produced by additive manufacturing, was also studied. Lower temperatures were obtained with a hexagon unit cell. Lastly, a comparison between the best HS in each category showed a lower thermal resistance for lattice HS. Despite the increase of at least 38% in pressure drop, a consequence of its frontal area, the temperature was 26% and 56% lower when compared to conventional pins and fins HS, respectively, and 9% and 28% lower when compared to the best pins and best fins of this study.

Numerical assessment on heat transfer performance of double-layered oblique fins micro-channel heat sink with Al2O3 nanofluid

This paper demonstrates a numerical study on heat transfer characteristics of laminar flow in a double-layered oblique finned heat sink using nanofluids with Al2O3 nanoparticles. Micro-channel heat sink with primary channel width of 0.5 mm with aspect ratio of 3 is employed. Instead of having conventional straight fins, oblique fins with narrow secondary channels are used. In this numerical study, single-phase fluid model with conjugate heat transfer is considered. The numerical modeling was first validated with existing data for double-layered conventional micro-channel heat sink having water (base fluid) as the working fluid. Numerical investigations on oblique finned micro-channel heat sink were then conducted for flow rates ranging from 3 ? 10?7 to 15 ? 10?7 m3/s, equivalent to primary channel inlet velocity in between 0.2 and 1.0 m/s. It was found that double-layered oblique finned configuration yields better heat transfer performance, inferred by the lower overall thermal resistance obtained as compared with that of double-layered conventional heat sink. Employing double-layered oblique finned heat sink, the heat transfer performance could be further enhanced, by using nanoparticles that are added into water-based fluid. It is found that the reduction of overall thermal resistance is proportional to the volume fraction of nanoparticles. Using cross-flow double-layered oblique finned configuration, the largest reduction in the overall thermal resistance can reach up to 25%, by using nanofluids with 4% volume fraction of Al2O3 nanoparticles.

Design of novel geometries for minichannels to reduce junction temperature of heat sinks and enhance temperature uniformity

• Numerical study is done to reduce temperature non-uniformity problem in heat sinks. • Novel combined minichannels are proposed and tested at a heat flux of 50 kW/m 2 . • Noticeable effects are detected on Δ T max,b and R t . • Maximum decrease of 11.5 K is found in Δ T max,b with η = 1.53 at Re = 900. Generally, various micro/minichannels are utilized to fabricate water-cooled heat sinks, but most of them have straight and simple geometries. To some extent, the heat sinks designed based on these geometries can dissipate the heat produced by electronic systems. However, there is still the temperature non-uniformity problem in heat sinks due to the limitation of pumping power ( P p ). In this article, several novel minichannels are designed to reduce the junction temperature of heat sinks and enhance the temperature uniformity. In these models, both the upstream and the downstream represent wavy structure with the same wave-amplitude but variable wave-lengths. To this end, 3D numerical simulations are carried out along with an experimental validation study. The coolant is water at the entrance temperature of 293 K and Reynolds number (Re) range between 100 and 900. The results show that the proposed minichannels have appreciable positive impacts on the thermal performance of heat sink, such that the maximum base temperature difference (Δ T max,b ) experiences a maximum decrease of 11.5 K, which results in a 2.35 times reduction in the total thermal resistance ( R t ). It is also found that despite a conflict between reducing R t and lowering P p , the novel minichannels show superior values of performance index ( η ) particularly at higher Re. Under the range of conditions studied, the maximum value of 1.53 is recorded for η at Re = 900.

Hydrothermal Investigation of the Performance of Microchannel Heat Sink with Ribs Employed on Side Walls

Abstract In the present study, conjugate heat transfer and fluid flow performance of microchannel heat sink has been investigated using dimensionless parameters. Novel ribs of four different types are introduced on the side walls of channel, which include trapezoidal ribs, rectangular ribs, hydrofoil ribs, and elliptical ribs. The performance evaluation has been conducted by comparing friction factor (f), Nusselt number ( N u Nu ), fluid bulk temperature ( T f {T_{f}} ), wall shear stress (τ), field synergy number ( F c Fc ), irreversible heat loss ( Q d {Q_{d}} ), and Bejan number ( B e Be ) in a Reynolds number, ranging from Re = 100 \mathit{Re}=100 to Re = 1000 \mathit{Re}=1000 . The results revealed that the addition of these novel ribs are helpful in improving the overall thermal and hydraulic performance of microchannel heat sink. From the results of Bejan number, it has been revealed that more than 96 % of losses are because of heat transfer. However, at low Reynolds number, the frictional losses can be neglected, because of very low fluid velocity. Moreover, it has been revealed that synergetic relation between velocity and temperature gradient becomes weaker at higher Reynolds number. Furthermore, it is clear from this study that elliptical ribs performed better in thermal aspects, whereas hydrofoil ribs performed better at hydrodynamic aspects.

Temperature Regulation of Photovoltaic Cells using Phase Change Material Heat Sinks Integrated with Metal Foam

This article investigates the cooling performance of Phase Change Material “PCM”-heat sinks integrated with porous metal that are attached to PV cells. Numerical simulations were carried out for a 2-dimensional configuration of a PCM-based heat sink subjected to uniform heat flux of 900W/m2 on the upper side and heat convection takes place at all other sides with a uniform convective heat transfer coefficient of 10 W/m2.°C. Two different PCMs were considered (n-Eicosane and RT44HC) and three values of metal foam porosity “e” were chosen as well (ε = 1.00, 0.97 and 0.90, where ε = 1.00 refers to no-metal foam case). Results showed that addition of metal foam enhances the cooling performance of PCM-based heat sinks. In the n-Eicosane based heat sinks, the PV-surface temperature was reduced by 6.31 °C and 7.00 °C for the 97% and 90% porosities respectively when compared to the no-metal foam case (100% porosity). On the other hand, in the RT44HC based heat sinks the PV-surface temperature was reduced by 5.50 °C and 6.15 °C for the 97% and 90% porosities respectively when compared to the no-metal foam case (100% porosity).

Numerical and artificial neural network modeling study on the first-law and second-law performance of a novel helical heat sink filled with water–silver nanofluid

This paper is devoted to studying the first-law and second-law performances of a novel helical heat sink (HS). The biologically synthesized water–Ag nanofluid is considered as the coolant. The impacts of volume concentration of nanoparticles ( $$\varphi$$ ), Reynolds number ( $$\mathrm{Re}$$ ) and geometrical parameters of HS on the hydrothermal aspects and irreversibility behavior of HS are evaluated, and their optimal values are found. It was noted that the intensification of both the $$\varphi$$ and $$\mathrm{Re}$$ causes an augmentation in the convection coefficient, average CPU temperature and maximum CPU temperature, while the thermal resistance diminishes by rising $$\varphi$$ and $$\mathrm{Re}$$ . In addition, the fluid friction and heat transfer irreversibilities growth by intensifying the $$\mathrm{Re}$$ diminished with the increment of $$\varphi$$ . Furthermore, the outcomes showed that the best first-law performance of the HS occurs at $$\varphi =1\%$$ and $$\mathrm{Re}=1500$$ , while the lowest irreversibility occurs at $$\varphi =1\%$$ and $$\mathrm{Re}=500$$ . Finally, the obtained numerical data were utilized to develop a predictive model for convective heat transfer coefficient, thermal entropy generation rate and frictional entropy generation rate. The accuracy of the models was evaluated based on three statistical indices including mean relative error percentage (MRE), root mean square error (RMSE) and coefficient of determination (R2). It was found that the $${R}^{2}$$ value for all the developed models is higher than 0.99.

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

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).

Effect of channel and fin geometries on a trapeze plate-fin heat sink performance

This study aims to achieve a minimum base temperature (or junction temperature) and hence better thermal performance. Trapezoidal curved plate-fin heat sink with dolphin fins and rectangular channel (Model-1) and trapezoidal curved plate-fin heat sink with dolphin fins, cut corner, and rectangular channel (Model-2) were designed and compared with a standard plate-fin heat sink. The effects of fins on the airflow and heat transfer in designed plate-fin heat sinks have been investigated numerically. The numeric results show that the use of fins and small changes in geometry significantly improve the heat transfer rate. Outcomes of the study showed 44–51% and 57–62% convective heat transfer enhancement compared with a standard plate-fin heat sink, without any overall mass augmentation, in Model-1 and Model-2, respectively. The presence of dolphin fins reduces the thermal resistance by up to 30%, which contributes to the overall thermal enhancement of the designed plate-fin heat sinks. Simulation results show that increasing the fins in areas close to the heat source and reducing the non-working areas significantly influence the thermal performance of heat sinks. The results also show that the trapeze plate-fin heat sinks with the different channel-fin geometries are superior to the standard trapeze plate-fin heat sink in thermal performance.

Numerical Study of Fluid Flow and Heat Transfer Characteristics in a Cone-Column Combined Heat Sink

Temperature has a great influence on the normal operation and service life of high-power electronic components. To cope with the increasingly severe heat problems in integrated circuits, an enhanced heat transfer factor E is introduced to evaluate the comprehensive heat transfer performance of microchannel heat sinks (MCHS). The computational fluid dynamics (CFD) software was used to numerically study the fluid flow and heat transfer characteristics in the cone-column combined heat sink. The research results obtained the velocity field and pressure field distribution of the heat sink structure in the range of 100 ≤ Re ≤ 700. When Re changes, the change law of pressure drop ΔP, friction factor f, average Nussel number Nuave, average substrate temperature T, and enhanced heat transfer factor E, are compared with the circular MCHS. The results show that the uniform arrangement of the cones inside the cone-column combined heat sink can change the flow state of the cooling medium in the microchannel and enhance the heat transfer. In the range of 100 ≤ Re ≤ 700, the base temperature of the cone-column combined heat sink is always lower than the base temperature of the circular MCHS, and the average Nusselt number Nuave is as high as 2.13 times that of the circular microchannel. The enhanced heat factor E is 1.75 times that of the circular MCHS, indicating that the comprehensive heat transfer performance of the cone-column combined heat sink is significantly better than that of the circular microchannel.

Thermo-hydraulic performance of a circular microchannel heat sink using swirl flow and nanofluid

Increasing the power and reliability of microelectronic components requires heat sinks with greater heat transport performance. This study investigates the hydraulic and heat transport performance of a silicon heat sink under a constant heat flux of 100 W/cm2 with liquid coolant running through parallel microchannels. The coupled heat transfer through the silicon walls and the coolant, modelled as a single-phase fluid, is examined over the Reynolds number range 100≤Re≤350 for micro-channels of circular cross-section, with a straight tape, and with a twisted tape that induces swirl in the flow. Al2O3 nanofluid at nanoparticle volume fractions ϕ = 0, 1, 2 and 3% is used as the coolant. The microchannel heat sink with swirl flow and with the highest nanoparticle volume fraction concentration provides the lowest thermal resistance and contact temperature. Whilst it has a higher flow resistance than the micro-channel with no tape cooled by pure water, it has a positive trade-off between the gains in cooling performance and in flow resistance. This makes these configurations attractive for designing more performing heat sinks for temperature limited or temperature sensitive micro-electronics.