Thermal Performance Of Heat Sink Research Articles

Thermal Performance of Metal Foam Heat Sink With Pin Fins for Nonuniform Heat Flux Electronics Cooling

Abstract In this paper, a concept of metal foam heat sink with pin fins (MFPF heat sink) is proposed to improve the cooling performance of high-powered electronics with nonuniform heat flux. Numerical simulations are carried out to investigate the thermohydraulic performance of MFPF heat sink, and the metal foam (MF) heat sink and traditional pin fin (PF) heat sink are employed for comparison. The capability of MFPF heat sink in handling nonuniform heat flux is examined under different power levels. It indicates that the MFPF heat sink greatly enhances the heat transfer performance, due to the common effects of the improved flow distribution and enhanced overall effective thermal conductivity (ETC). Results also show that the MFPF heat sink promotes the improvement of the bottom wall temperature uniformity. Porosity has more pronounced effects on heat transfer performance of MFPF heat sink than pore density. A nonuniform distribution heat flux (15–80–15 W/cm2) can be successfully dissipated using the proposed MFPF heat sink with the junction temperature below 95 °C at Re of 500.

Thermal performance and entropy generation of novel X-structured double layered microchannel heat sinks

A novel X-structured Double layered Microchannel Heat Sink (X-DMHS) is proposed for performance augmentation on the traditional rectangular Double layered Microchannel Heat Sink (DMHS). The overall flow and thermal performances of parallel-flow and counter-flow arrangements on X-DMHSs are studied, and the entropy generation from the second law perspective is also quantitatively analyzed. From the analysis of the pressure drop penalty, thermal performance and entropy generation rate, it is found that the proposed X-DMHSs show much superior performance either from the heat transfer performance or from the second law perspective. The design offers higher entropy generation number and better thermal uniformity on substrate, meaning that proposed X-DMHSs can control the thermal gradients more significantly and lower the highest temperature on the heated substrate more effectively with affordable rise of pumping power as compared with the corresponding traditional DMHS.

Influence of Changing Porosity and Height of Fins on Thermal Performance of The Metal Foam Heat Sink: Numerical Investigation

Abstract— With the major advances in technology, the extreme need for more powerful and efficient electronic devices and equipment has increased, that is requiring more heat generation as a result. So, it is necessary to find a cooling method commensurate with heat generated. This leads to the use of the foam heat sink which is considered as one of more powerful cooling methods for this purpose. The target of this work is to numerically investigate the impact of changing the porosity and the ratio between height of the fin respect to its length on base temperature and heat transfer coefficient in the case of natural convection conditions. The dimensions of the foam fins were 100 * 10 in mm (length * width) and the spacing between fins was 8 mm, while the height of fins was variable with ratio ranging from 0.2 to 2.4. The porosity of model was changing from 0.95 to 0.71 with fixed pore density of 10 PPI. The investigations have been performed by using ANSYS Fluent software (R16.1) and the model of a local thermal non-equilibrium (LINE) has been used in the analysis where, the temperature of the solid part in foam matrix and the fluid are solved individually in energy equation. The heat fluxes were various from 4 to 30 W, and air has been used as a working fluid. The results showed that the average improvement in base temperature of the heat sink is 16.7 %, and the maximum enhancement of heat transfer coefficient reaches about 21.3%, when the porosity reduced from 0.95 to 0.79. The highest enhancement in base temperature and heat transfer coefficient obtains when the height to length ratio is (2.2) and estimated by 30 % and 83.8% respectively, compared with the ratio of (0.2).

Theoretical and experimental advances on heat transfer and flow characteristics of metal foams

Open cell metal foam can be applied to greatly improve thermal performance of heat sink and heat exchanger, so that it has been widely used in the fields of thermal (or heat) control system of aerospace vehicle and energy utilization system and become a very important topic for research in the aerospace thermophysics field, and more and more attentions have been attracted. The optimal design of metal foam heat transfer devices is based on the understanding the flow and heat transfer characteristics in metal foam. This article reviews some recent progresses of theoretical and experimental researches on heat transfer enhancement and flow characteristics of metal foam. We found that the pore cell simplification models of metal foams generally fall into four categories, among which the most commonly used cell model is Kelivin model. Some exploratory works performed by the current authors are also introduced, such as the effect of boundary conditions on the heat transfer enhancement; the theoretical modelling of interfacial convective heat transfer taking into account heat conduction between foam ligaments; and the flow characteristics under relatively high velocity. The analytical results show that the flow characteristics of metal foam at relatively high speed are completely different from those at low speed, a further thorough study of the heat transfer and flow characteristics of metal foam is necessarily required. In this paper, two types of partial filling techniques are discussed. The heat transfer performance of partially filled tubes was evaluated by both the performance evaluation criteria and the performance evaluation plot of enhanced heat transfer techniques oriented for energy-saving. The results show that the filling type of metal foam have a significant impact on its heat transfer enhancement performance. Therefore, the filling method of metal foam should be further studied, in order to optimize the thermophysical properties of heat transfer devices.

MHD forced convection of nanofluid flow in an open-cell metal foam heatsink under LTNE conditions

In this paper, nanofluid forced convective heat transfer through an open-cell metal foam heatsink under a uniform heat flux, numerically has been investigated. A uniform magnetic field has been applied to the nanofluid flow. For the momentum equation, Darcy–Brinkman model and, for the energy equation, two-equation model under the condition of fully developed from the thermal and hydrodynamical standpoints have been used. In recent study, by utilizing a numerical method, an attempt was made to avoid a complete and complex CFD approach. To validate the results, the dimensionless parameters such as non-dimensional velocity and temperature, pressure gradient and Nusselt number have been compared with previous researches and a good agreement appeared. Eventually, the effects of different dimensionless parameters such as porosity, Hartman number, nanofluid volume fraction, Reynolds number, thermal conductivity ratio and pore density on the hydrodynamical and thermal characteristics of heatsink have been investigated. The outcomes show that the rise of pore density and Hartman number and the decline of the porosity will enhance the thermal performance; however, it also will reinforce the resistance to the flow through the porous media. Focusing on results illustrates that Nusselt number variation for increasing porosity from 0.85 to 0.95 at the minimum and maximum of the pore density are $$\left( {\Delta {\text{Nu}}_{{\left(\upvarepsilon \right)}} } \right)_{{\upomega = 10}} = - 331.7$$ and $$\left( {\Delta {\text{Nu}}_{{\left(\upvarepsilon \right)}} } \right)_{\omega = 60} = - 367.8$$ , and these values for friction factor are equal to $$\left( {\Delta f_{{\left(\upvarepsilon \right)}} } \right)_{{\upomega = 10}} = - 22.3$$ and $$\left( {\Delta f_{{\left(\upvarepsilon \right)}} } \right)_{{\upomega = 60}} = - 793$$ , respectively. On the other hand, increasing Hartman number from 0 to 100 would change the Nusselt number and friction factor as $$\left( {\Delta {\text{Nu}}_{{\left( {\text{Ha}} \right)}} } \right)_{{\upomega = 10}} = 9.4$$ , $$\left( {\Delta {\text{Nu}}_{{\left( {\text{Ha}} \right)}} } \right)_{{\upomega = 60}} = 0.2$$ , $$\left( {\Delta f_{{\left( {\text{Ha}} \right)}} } \right)_{{\upomega = 10}} = 213$$ , and $$\left( {\Delta f_{{\left( {\text{Ha}} \right)}} } \right)_{{\upomega = 60}} = 211$$ , respectively. The amount of Hartman and Reynolds numbers effects on the heat transfer rate depends on the pore density. In other words, when the pore density becomes saturated, the effects of these parameters decrease. In addition, the use of nanofluid will improve the heatsink thermal performance.

Numerical Investigations of Mini-Channel Heat Sink for Microprocessor Cooling: Effect of Slab Thickness

High heat generation in microelectronics devices is an inevitable consequence of high processing loads. One of the important factors in design of electronic devices is to design a smart cooling system to remove the generated heat well in time for a reliable and longer life. Water-cooled heat sinks are replacing air-cooled heat sinks with the rapid compactness and high process requirements. In this work, we introduced a slab in mini-channel and evaluated the thermal performance of mini-channel heat sink. The boundary layer separately develops in upper and lower portions of channel, which enhanced the heat transfer. We changed the thickness of slab from 0.2 to 1.6 mm for fin spacing of 0.5 mm and 1 mm, respectively, to determine the effects of thickness on overall thermal performance of heat sink. The computed values were then compared with the data available in the literature without slab. The minimum base temperatures recorded for 0.2-mm-thick slab with fin spacing of 0.5 mm and 1.0 mm were 40.1 °C and 42.4 °C, respectively. This represents a reduction of 12.5% and 16.2%, respectively, in the base temperature as compared to the base temperature without a slab.

Experimental investigation on thermal performance of plate fin heat sinks with nano PCM

In this study, electronic devices are experimentally examined to improve the thermal performance of the plate fin heat sink. It is performed on the basis of the paraffin wax used as a phase change material (PCM) filled in a heat sink plate. The aim of the study is to select the most efficient SiO2 volume fraction in paraffin wax to be filled in a heat sink with a plate finish. The SiO2 is considered to be a nano-particle and 1%, 3%, and 5% of SiO2 volume is selected for the preparation of nanoPCM. At the base of the plate fin heat sink, a constant heat source is applied. A plate fin heat sink is selected to quantify the effect of nanoPCM as a reference heat sink. The effect of thermal performance of heat sinks was examined using a different volume fraction of nanoPCM. The thermal performance comparison is carried out with and without PCM for the plate heat sink of Reynolds number 4000- 16000. In order to find the effect of PCM and variable Reynolds number, the investigation of the plate fin heat sink is examined. The results showed that the inclusion of PCM (paraffin wax and SiO2-based nanoPCM) in the heat sink plate provides better cooling performance and keeps the desired temperature. The results show that the heat sink based on PCM enriched with nanoparticles provided better thermal performance compared to the heat sink with a simple PCM. The thermal performance of the SiO2 based nanoPCM 3% volume fraction is better than 1% volume fraction and the heat sinks of the plate finish.

Augmentation of Thermal Performance of Plate Fin Heat Sink

Heat sinks are popularly used in various industrial applications to cool electrical, electronics and automobile components. They are useful in removing the heat from the surfaces at elevated temperatures. The life of such devices depends on their operating temperature. Heat sinks are important parts of thermal management systems of most of these devices eg: Diods, thyristers, high power semiconductor devices such as integrated circuits of inverters, audio amplifier, microprocessors, microcontrollers etc. In many situations where heat transfer is by free convection where convective heat transfer coefficient is low, fins are the best solution because of their less cost and trouble free operation. The weight and size of equipment are the most important parameters of design. Present day demand, the use of compact systems in every application which leads to higher packing density. The failure rate of electronic equipments increase exponentially with the temperature. Also the high thermal stresses in the solder joints of electronic components mounted on circuit boards resulting from temperature variation are major causes of failure. Therefore thermal control has become an important factor in the design and operation of electronic equipment. The most preferred method for cooling these systems is passive cooling because it is cost effective and reliable. This leads to focus on development of effective fin heat sink. To make heat sink effective, geometry and orientation of the heat sink as well as heat transfer augmentation techniques plays important role. This paper highlights the use of heat sinks in electronic cooling applications and review of related literature of improving the heat transfer performance of plate fin heat sinks by surface modifications, interrupting the boundary layer and changing the orientation.

Augmentation of Thermal Performance of Plate Fin Heat Sink

Heat sinks are popularly used in various industrial applications to cool electrical, electronics and automobile components. They are useful in removing the heat from the surfaces at elevated temperatures. The life of such devices depends on their operating temperature. Heat sinks are important parts of thermal management systems of most of these devices eg: Diods, thyristers, high power semiconductor devices such as integrated circuits of inverters, audio amplifier, microprocessors, microcontrollers etc. In many situations where heat transfer is by free convection where convective heat transfer coefficient is low, fins are the best solution because of their less cost and trouble free operation. The weight and size of equipment are the most important parameters of design. Present day demand, the use of compact systems in every application which leads to higher packing density. The failure rate of electronic equipments increase exponentially with the temperature. Also the high thermal stresses in the solder joints of electronic components mounted on circuit boards resulting from temperature variation are major causes of failure. Therefore thermal control has become an important factor in the design and operation of electronic equipment. The most preferred method for cooling these systems is passive cooling because it is cost effective and reliable. This leads to focus on development of effective fin heat sink. To make heat sink effective, geometry and orientation of the heat sink as well as heat transfer augmentation techniques plays important role. This paper highlights the use of heat sinks in electronic cooling applications and review of related literature of improving the heat transfer performance of plate fin heat sinks by surface modifications, interrupting the boundary layer and changing the orientation.

Thermal and hydrodynamic performance of a microchannel heat sink with carbon nanotube nanofluids

Increasing heat fluxes in decreasing sizes of a microchannel heat sink have necessitated studies into better systems, in particular a more capable coolant for improved thermal management. Nanofluids have been at the forefront with their higher thermal conductivity as compared to the base fluid alone. However, few investigations have looked into the role played by surfactants, a component used for dispersion and stability of nanofluids, and their influence on thermophysical properties and thermal performance. Optimized performances of carbon nanotube nanofluids with different surfactants at different volume fractions under laminar flow are studied. Using the thermal resistance model and experimental data for thermal conductivity and viscosity of nanofluids, the thermal resistance and pumping power are simultaneously minimized using multi-objective genetic algorithm. Results showed that the nanotube nanofluid with lignin as the surfactant performed better thermally and hydrodynamically, due to lower viscosity at high carbon nanotube concentration compared to the nanotube nanofluid with sodium polycarboxylate surfactant. As an example, a 29% and 28% increase in pressure drop is found for sodium polycarboxylate-based nanofluid at a volume fraction of 0.1% for a circular and square MCHS, respectively. A similar pattern is observed at higher volume fraction as well, even higher pressure drop with increasing volume fraction. Also, it is shown that microchannel heat sink with circular cross section performed better than that with square section.

Heat and fluid flow analysis of metal foam embedded in a double-layered sinusoidal heat sink under local thermal non-equilibrium condition using nanofluid

The present study aims to enhance the hydrothermal performance of a porous sinusoidal double-layered heat sink using nanofluid. The optimum thickness of metal foam (nickel) for different Reynolds numbers ranging from 10 to 100 for the laminar regime and Darcy numbers ranging from 10−4 to 10−2 is obtained. At the optimum porous thicknesses, nanofluid (silver–water) with three volume fractions of nanoparticles equal to 2, 3, and 4% is employed to enhance the heat sink thermal performance. Darcy–Brinkman–Forchheimer model and the local thermal non-equilibrium model or two equations method are employed to model the momentum equation and energy equations in the porous region, respectively. It was found that in the cases of Darcy numbers 10−4, 10−3, and 10−2 the dimensionless optimum porous thicknesses are 0.8, 0.8, and 0.2, respectively. It was also obtained that the maximum PEC number is 2.12 and it corresponds to the case with Darcy number 10−2, Reynolds number 40, and volume fraction of nanoparticles 0.04. The validity of local thermal equilibrium (LTE) assumption was investigated, and it was found that increasing the Darcy number which results in an enhancement in porous particle diameter leads to some errors in results, under LTE condition.

Numerical Investigation of Inclination on the Thermal Performance of Porous Fin Heatsink using Pseudospectral Collocation Method

Numerical Investigation of Inclination on the Thermal Performance of Porous Fin Heatsink using Pseudospectral Collocation Method

Investigation of a computer CPU heat sink under laminar forced convection using a structural stability method

In the present study, the thermal performance of an air-cooled, flat-plate heat sink in forced convection was performed using a three-dimensional analytical model. To validate the present model, this solution is compared with numerical and experimental results that agree. This research studies the influence of heat sink thermal performance and of environmental parameters on the heat sink’s stability against thermal stress, which is essential for manufacturers’ goals. The effective parameters on heat transfer rate from the surface of heat sink were investigated. Reynolds and Nusselt numbers, heat transfer coefficient, fins height, and fins number were studied under various air flow velocities. In addition, the thermal stress (structural stability method) was investigated. Enhancement of the airflow velocity caused the Nusselt number value to incline, which increases the heat transfer coefficient. Increasing the Reynolds number from 3.80*103 to 2.28*104 leads to less thermal stress by 47.36%, less deformation by 50%, less surface temperature by 28.57%, and, consequently, less geometry failure. Results depicted that pure convection has less heat transfer by 1.66% compared with convection-radiation heat transfer, and enhancing the fins number and fins height reduces the surface temperature by 25% and 20%, respectively. As a result, the chosen range of the Reynolds number is totally suitable for this high-temperature device that does not allow thermal stress to deform the fins of the heat sink.

Numerical investigation of heat transfer enhancement in plate-fin heat sinks: Effect of flow direction and fillet profile

Many researchers have studied the thermal performance of heat sinks, however to the best knowledge of the authors, the effect of flow direction (place of fan) on the thermal performance of plate-fin heat sinks with fillet profile have not yet been investigated. In this paper, the investigation develops a computational fluid dynamics (CFD) model, validated through comparison with an experimental data from the literature, which demonstrates the effect of flow direction and fillet profile on the thermal performance of plate-fin heat sinks. In particular, a plate-fin heat sink with fillet profile subject to parallel flow has been compared with the conventional design (plate-fin heat sink without fillet profile subject to an impinging flow) and satisfactory results have been perceived. The results of this study show that the base temperature along with the thermal resistance of the heat sink is lower for the proposed design. Therefore, the developed approach has strong potential to be used to improve the thermal performance of heat sinks and hence to develop more advanced effective cooling technologies.

Effect of Knurled Fin Surface on Thermal Performance of Perforated Fin Heat Sink

Fabricating perforations in fins causes improvement in heat dissipation rate with lower pressure drag up to a specific perforation number and size of perforation. Again knurled surfaces augment heat transfer rate due to turbulence promotion as well as substantial increase in surface area. The present work investigates thermal performance of heat sink using perforated pin fins with different knurled surfaces. Three-dimensional computational fluid dynamics simulations have been performed to explore the effects of various different knurling geometries on fin surface, perforation number, and size on system performance. A multicriteria decision-making optimization method such as Multi-Objective Optimization under Ratio Analysis (MOORA) has been applied to select the best heat sink configuration. It has been observed that the rate of heat transfer for perforated fins up to a particular perforated area is always greater than the solid fins, and with the variation in knurling geometry on fin surface, heat dissipation rate enhances significantly. Conversely, pressure drop around heat sink decreases with the increment of number and size of perforations. However, due to knurling on fin surface, pressure drop increases. Finally, exergy analysis has also been carried out to calculate second law efficiencies of circular perforated fins using different knurling patterns with increasing number of knurling teeth.

Influence of Aspect Ratio on Thermal Performance of Heat Sink using Ansys

Influence of Aspect Ratio on Thermal Performance of Heat Sink using Ansys

Towards Thermal-Acoustic Co-Design of Noise-Reducing Heat Sinks

Several thermal management applications involve fan-mounted heat sinks that result in fan-generated noise as an undesired by-product. These applications require noise reduction and attempt to reduce noise using separate muffler devices. However, space for separate heat-sinking and noise-reducing functionalities may be challenging in high-performance applications such as electronics cooling, data centers, automotive, aviation, and various others. A first-principles-based approach for combined heat sinking and noise reduction in the same functional volume is discussed in this paper. This paper reports on thermal-acoustic co-design of 3-D periodic porous foam structures. In order to enable a design strategy, an analytical framework that characterizes the governing performance indicators of both acoustic and thermo-fluid design on a unifying platform is laid out. A combination of analytical and phenomenological models is used to predict the absorption coefficient, transmission loss (TL), and other acoustic performance indicators. For thermal predictions, an experimentally validated semiempirical model is presented to estimate thermal resistance and static pressure drop of foam heat sink as a function of geometrical parameters as well as flow rates. Octave-band weighted values of acoustic indicators are then compared against thermal indicators to investigate thermal-acoustic co-design aspects. As hydraulic pore radius of porous foam decreases, the acoustic absorption coefficient increases reaching local maxima. Concomitantly, the pore radius decrease not only increases the absorption coefficient while dissipating heat, but also increases the heat sink pressure drop. For a chosen sound absorption region of interest, there exists a particular static pressure drop that maximizes heat sink dissipation for a given radius. The paper concludes by reporting TL and heat sink thermal performance for a generic electronics cooling configuration while elucidating the nuances of the proposed heat sink design using a thermal-acoustic index.

Similarity solution of air and nanofluid impingement cooling of a cylindrical porous heat sink

In the present paper, a numerical study on flow and heat transfer of air/nanofluid impinging jet flow through a cylindrical porous heat sink has been done. The cooling fluid flows uniformly through the porous foam over the hot disk. Conservation equations of mass, momentum and energy in form of partial differential equation, by using similarity variables, converted to nonlinear ordinary differential equations and finally these equations have been solved numerically. Also, results are validated through comparison with those of a commercial CFD code with an acceptable agreement. In this study, effects of dimensionless parameters in the form of geometrical, porous media characteristics and cooling fluid properties on the velocity profile, temperature profile and average Nusselt number have been scrutinized. Results indicate that addition of nanoparticles, thermal conductivity ratio increment and aspect ratio reduction will enhance the heat sink thermal performance.

Heat transfer and airflow characteristics enhancement of compact plate-pin fins heat sinks – a review

Plate-pin heat sinks are widely used for the electronic cooling system, internal combustion IC engine, cooling of gas turbine blades and other different applications to enhance the thermal performance of heat sinks due to simplicity, low cost, and a reliable manufacturing process. However, compact heat sinks give higher pressure drop compared with other types of heat sinks. The purpose of this article is to summarise the main advantages and disadvantages of the compact heat sink with some recommendation studies for future works heat sink thermal airflow experiment and simulations. Furthermore, the research attempts to highlight the importance of balance the relationship between the hydraulic performance and the thermal performance of compact heat sinks.

Thermal performance of micro-channel heat sink with metallic porous/solid compound fin design

Rapid development of large-scale integrations of electronic circuits resulted in increasing requirements for chip power dissipation. In this study, a concept of micro-channel heat sink with the metallic porous/solid compound fin design was developed and numerically investigated. Computational investigations were carried out to analyze the effects of metallic porous fins on the hydraulic and thermal performances, and to determine the optimal dimensionless porous fin thickness for designing the porous/solid compound fins. The traditional solid fin heat sink is selected as the comparison model. The results indicate that the viscous shear stress is reduced at the fluid and porous fin interfaces, which leads to decreased pressure drop through the porous fin heat sink. Whereas, the heat transfer performance deteriorates when the solid fins are completely replaced by the porous fins. The novel design of porous/solid compound fin demonstrates more favorable in the hydraulic and thermal performances. Both the pressure drop and the overall thermal resistance are substantially decreased, and the optimal dimensionless porous fin thickness for the compound fin heat sink is approximately 0.2. The presented compound fin heat sink is capable of effectively enhancing the cooling performance for high-powered electronics.