Pin Fin Heat Research Articles

Numerical investigation on the characteristics of flow and heat transfer enhancement by micro pin-fin array heat sink with fin-shaped strips

Targeted at improving microfluidic cooling for the use of micro heat sink in electronic chips, a novel fin-shaped pin-fin array heat sink is proposed. In this study, the mechanism of flow and heat transfer, the arrangements of pin-fin layout, the characteristics of single-phase flow and heat transfer among the micro cylinder pin-fin heat sink, micro fin-shaped pin-fin heat sink of A、B、C types are investigated. It’s showed that stagger micro fin-shaped A pin-fin (SMFAP) exhibits the best hydro-thermal performance. At high Reynolds number, the average Nusselt number of SMFAP reaches up to two times of the in-line micro cylinder pin-fin (IMCP). Moreover, the structure of fin-shaped pin-fin can enhance heat transfer by increasing Nu, while weaken heat transfer by large pressure drop. Therefore, the non-dimensional parameter PEC is adopted to evaluate the heat transfer performance of heat sink. When Re is 800, the PEC of SMFAP reaches to its maximum value of 1.4. SMFAP can effectively enhance heat transfer, while stagger micro fin-shaped B pin-fin(SMFBP) and stagger micro fin-shaped C pin-fin (SMFCP) are not obviously. It’s concluded that different structures of fin-shaped pin-fin will affect the separation point of flow, thus affecting the size of vortex behind the cylinder.

Optimal structure of a water cooled pin fin heat sink by Taguchi method depending on various requirements

Optimal structure of a water cooled pin fin heat sink by Taguchi method depending on various requirements

FLUID FLOW AND HEAT TRANSFER BEHAVIOR IN DISTINCT ARRAY OF STEPPED MICRO-PIN FIN HEAT SINK

In this paper, numerical analysis has been performed on micro-pin fin heat sinks with novel arrangements of the fins. Varying the fin height in an array of two, three, and four fins evolves stepped-type pin fin heat sink. Geometry selection of all seven configurations of the heat sinks is made on the basis of equal footprint area as well as net convective surface area. Single-phase liquid water has been used as a cooling medium where inlet Reynolds number (Re) varied from 200-600. Comparative numerical results are presented through the illustration of temperature distribution, Nusselt number (Nu), pressure drop, velocity contour, and thermal performance factor. Estimated findings clearly indicate that the overall performance of the stepped configurations is better than uniform fin height. Moreover, arrays of increasing fin heights facilitate favorable flow behavior compared to decreasing fin height; consequently, they support higher heat transfer rate from the heat sink. Among the stepped heat sinks, THSI (three-stepped increasing) configuration exhibits superior performance due to distinct coolant flow and favorable heat dissipation circumstances originated by constructive fin arrangements. Similarly, the thermal performance factor of THSI is found to be consistently higher compared to all other heat sinks.

Influence of fin orientation on the natural convection of aqueous-based nano-encapsulated PCMs in a heat exchanger equipped with wing-like fins

The heat transfer enhancement in pin-fin heat exchangers is achieved by fluid mixing, disruption of the thermal-viscous boundary and the extension of the effective surface area for maximum heat exchange. The orientation and configuration of the fins are among the prime factors influencing the performance of these heat exchangers. Therefore, the present study investigates the combined influences of fin angle (0≤ζ≤270), arrangement and position of the wing-like fins on the natural convection of aqueous-based nano-encapsulated phase change material (PCM) in a fin heat exchanger. The analysis is performed for Rayleigh and Stefan numbers of 1e3-1e5 and 0.2 respectively by considering the PCM concentration of 0.05. The flow is assumed to be laminar, incompressible and Newtonian. The results demonstrate that the vertical alignment of the fins contributes to the augmentation of the thermal performance compared to the horizontally arranged fins. At the larger Rayleigh number, the mode of heat transfer is predominantly convective and thermal performance slightly deteriorates due to the blockage caused by adjacent fins. For low Rayleigh number, the conduction is the primary mode of heat transfer between the source and sink fins. This phenomenon is crucial to determine the heat exchanger thermal performance.

Thermal reliability-based design optimization using Kriging model of PCM based pin fin heat sink

This paper deals with the thermal reliability optimization of a pin fin heat sink (HS) filled with phase change material (PCM) in order to study the heat transfer performance for cooling of electronic devices. Aluminium is taken to carry out the pin fin heat sink with a constant volume fraction of 9% by choosing 72 pin fins. Paraffin wax is used as PCM inside the heat sink to retain the heat produced by the electronic device. A reliability-based design optimization (RBDO) is addressed to determine the optimum thermal configuration of the pin fin heat sink that satisfies the desired reliability. The presented methodology is summarized by the combination of the 3D finite element simulation (FES), the Kriging substitution model and the optimization procedure. The surrogate model is built and validated using two metrics such as error predictions and cross validation (CV). A comparison of the number of training points shows that the Kriging predictor with 100 Latin hypercube sampling (LHS) points provides a better approximation of the original model. Thermal optimization results show that the time taken by the latent heating phase of the optimal design is higher than that obtained by the baseline model. With the reliability optimization, the maximum temperature of the optimal design was reduced by 30%.

Natural Convection Heat Transfer from a Heat Sink with Hollow/ perforated circular Pin Fins (Dept.M)

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Heat transfer study on different surface textured pin fin heat sink

The flow and heat transfer characteristics of different surface texture pin fins were experimentally investigated. The pin fin outer surface texture has been modified to different threaded surface texture (i.e., Metric, Worm, ACME, Buttress, Sharp V, Whitworth and square thread) without changing cross-sectional areas. The Reynolds number based on hydraulic diameter was varied from 2500 to 4500. This study reveals that threaded surface pin heat sink is 18.13% higher heat transfer than plain pin heat sink. In terms of specific performance consideration, threaded surface textures pin fins shows impending substitute design to plain circular pin fins. The threaded surface texture pin has decreased aerodynamic consequence compared to plain circular pin. The pressure drop across heat sink is 21.4% lesser in plain pin heat sink than screw surface pin heat sink. The thermal resistance difference between experimental and CFD analysis is 4.08%. The threaded texture increases surface area, flow turbidity and delays flow separation and these factors enhances the heat transfer.

Numerical investigation of thermo-hydrodynamic performance of triangular pin fin heat sink using nano-fluids

Cooling of miniaturized electronic components is of greater need to enhance the reliability, performance and life of the electronic component. Miniaturized devices with fins is an advanced cooling method used to maintain the surface temperature of the component by providing additional surface area for heat dissipation, Different geometries of extended surfaces and different cooling fluids are studied to enhance the thermal- hydro performance. This paper presents a numerical study of flow and heat transfer characteristics of three- dimensional heat sink with triangular pin fin using water and ethylene glycol (EG) as base fluid. Later the base fluid mixed with diamond powder (DM), aluminum oxide powder (Al2O3) and copper powder (Cu) nanoparticles with 2% and 4% volume concentration is considered. The study is carried out for Reynolds number ranging 100–900 subjected to constant heat flux 10 W/cm2. A non-dimensional parameter thermal performance index is used to access the heat transfer characteristics of a heat sink. Results indicate heat dissipation rate of the finned heat sink was enhanced employing nanofluids, however, the performance index of nanofluids was slightly affected compared to base fluids. Pressure drop for water-based copper nanoparticles for 4% volume concentration is 9.4% greater compared to pure water. The heat dissipation rate enhances by 20.31% for ethylene glycol-based nanofluids and by 6.54% for water-based nanofluids. The conservative equations for fluid and solid domain are solved using FLUENT 16.2.

Experimental and Cfd Analysis of Heat Transfer Rate in Multi Air Jet Impingement Over A Flat Plate and Pin-Fin Heat Sink

In this paper reports the results of investigation of heat transfer performance of in compression air jet impinging of heated surface over a flat plate & pin-fin heat sink. To mimic the computer processor of flat plate and pin fin dimensions are 120mm*75mm and pin height is 5cm and fin radius is 1cm and L/d ratios are 5,10,15respectively. By using this simulation in Ansys fluent software to perform the turbulent jet impingement on a surface. The bottom surface of the plate is supply constant heat flux and top surface of the plate is cooled by an impingement jet of air. It has two equations are used k-w model and shear stress transport to handle the turbulent jet. The result of flat plate heat sink is compare the Experimental and simulation is higher at 0.89% of experimental to compare numerical and Nusselt is higher at 3.35% of numerical to compare the experimental and heat transfer coefficient is higher at 4.51% of numerical to compare the Experimental and result of pin fin heat sink is compare the Experimental and numerical is higher at 0.23% of experimental to compare the numerical and Nusselt number is higher at 0.71% of numerical to compare the experimental and heat transfer coefficient is higher at 0.88% of numerical to compare the experimental. The effect of L/d ratios of jet impingement over a flat plate and pin fin heat sink on the heat transfer performance of the heated surface of investigated.

A comprehensive study of pin fins cooling channel for a single‐cell concentration photovoltaic system under ultra‐high concentration ratios

Analysis of the single-cell concentration photovoltaic (CPV) system is challenging due to the high thermal stress across the solar cell surface area inducing extreme degradation of the electro-mechanical behavior. Although the good thermal performance shown by the passive cooling using heat sinks and the different optical configurations based on Cassegrain and Fresnel lens designs, the experimentally achieved concentration ratio (CR) is still below 5800 suns. The actively cooled heat sink integrating millimeter-scale pin-fin array inside a cooling channel can be promising toward minimum heat sink weight and maximum discharge of the generated heat. The current study presents a comprehensive analysis of a pin-fins cooling channel for a single-cell CPV system under ultra-high CRs. The thermal performance and the hydraulic resistance of five pin-fin heat-sink configurations were performed at different CRs and low Reynolds number for an Aluminum substrate material. The inline pin-fins heat sink (PFHS) displayed the minimum average cell temperature for all Reynolds numbers with thermal performance higher than its closest successor by 9.07%. The thermal performance and the pressure drop showed more dependence on streamwise spacing rather than spanwise spacing for all tested staggered pin-fin heat sinks. Pressure drop drastically increased at higher Reynolds number, Re = 726, for the inline pin-fin heat sink reaching a value of 288.20 Pa due to higher disturbance in the streamwise direction. The results demonstrate that the inline pins-fin heat sink with a constant distribution of circular axial grooves (plugs) along each pin can keep the solar cell within a safe operating temperature, that is, 80°C, for CR up to 15 000 suns at an ambient temperature below or equal to 35°C.

Experimental investigations of conical perforations on the thermal performance of cylindrical pin fin heat sink

This paper deals with experimental investigations of heat transfer and friction factor characteristics of perforated pin fin heat sink tested in a rectangular channel by using forced convection. Cylindrical pin fins with conical perforations on the lateral surface area were arranged in staggered arrays on the base plate to form heat sink. Two combinations, such as solid fins and fins with conical perforations, were compared. The effect of number of conical perforations and size of conical perforation on thermal performance of heat sink was studied in detail. The heat sinks were subjected to variable air flow rate (10,000 ≤ Re≥ 30,000) in the turbulent regime and constant heat flux input. The results found that with an increase in the number of conical perforations from 2 to 5 results in higher heat dissipation rates and lower pressure drop. With an increase in the size of conical perforation, heat transfer rate initially increases, attains maximum values and then decreases. This is due to the reduction in vertical heat transfer rate through fin by conduction, which shows adverse effects on the overall heat transfer rate by convection. The purpose of using conical perforation instead of circular perforation was to increasethe velocity of air passing through perforation. This affects the turbulence of working fluid at heatsink and ultimately influences heat transfer rate from heat sink.

An unbiased method for PRF-shift temperature measurements in convective heat transfer systems with functional parts made of metal

The purpose of this study is to provide a PRF-shift method for fluid temperature measurements in convective heat transfer systems, which contain functional parts made of metal. Such measurements are extremely useful to examine and design convective cooling systems for industrial devices. Metals like copper seem inevitable for such applications because no commonly available non-metallic material reaches the same level of thermal conductivity as for example copper. In MRI, electrically conductive parts embedded in the measured sample are known to produce various kinds of errors including errors in the image phase caused by eddy currents. Two methods are compared that can be used to remove the eddy currents induced phase: via the phase difference of two readouts at different echo times and via the sum of the phase of two acquisitions with reverse gradient polarity and same echo time. The latter method, termed Rot-Echo, provides a better measurement efficiency because of higher temperature sensitivity. Also, this technique is able to directly measure the eddy currents induced phase map. After verification in a stationary water experiment, the Rot-Echo method was applied to time-averaged temperature measurements in a Pin Fin heat exchanger, comprised of water flow that is heated by an array of copper pins. The temperature fields acquired in the Pin Fin heat exchanger under stable thermal-hydraulic conditions agreed well with data from temperature sensors. No eddy currents effects were visible in any of the data sets in the vicinity of the copper rods. In conclusion, this study shows that unbiased PRF-shift temperature measurements are feasible in complex flow systems even if metallic material is used for the functional parts.

Change of Cooling Performance of Pin Fin Heat sinks by Pulsating Flow

Change of Cooling Performance of Pin Fin Heat sinks by Pulsating Flow

Employing elliptical pin-fins and nanofluid within a heat sink for cooling of electronic chips regarding energy efficiency perspective

The two-phase investigation of a silver–water nanofluid flow within the elliptical pin-fin heat sink regarding different nanoparticle volume fractions, fin densities, and Reynolds numbers is performed aimed at enhancing the electronics cooling performance. Five volume fractions and four fin densities are considered. The mixture-based two-phase model is implemented for modeling the flow and heat transfer, while turbulent flow is modeled using the four-equation transition Shear Stress Transport (SST) model. Adding the nanoparticles into the base fluid has an appreciable positive effect on the heat transfer coefficient (h), surface temperature, thermal resistance, and temperature uniformity of the surface, such that the thermal resistance experiences a maximum reduction of 16.2% when the volume fraction elevates by 0.4% at fin density of 0.168 and Reynolds number of 2500, which results in a 25.5% enhancement in the h. Furthermore, the heat transfer coefficient significantly elevates when the fin density increases, whereby the maximum increment in the h is obtained around 49.6% by the increase of the density from 0.036 to 0.168 at volume fraction of 0.4% and Reynolds number of 2500. Moreover, the pumping power and figure of merit have ascending trends by the increment in the volume fraction or fin density.

Effect of heat sink design on the thermal characteristic in computational fluid dynamics analysis

The thermal management in the electronic device or system using the heat sink is important to ensure the device or system operating under the allowable temperature. The present study aims to investigate the thermal characteristic (i.e., temperature distribution) of the various heat sink designs via computational fluid dynamics (CFD) analysis. The electronic cooling process of the heat sink is carried out via CFD software. The temperature distribution of the various heat sink designs (i.e., plate fin, circular pin fin and rectangular fin) was analyzed and compared. The CFD analysis revealed the plate fin heat sink has lowest temperature distribution on the fin region. High temperature distribution was observed on the pin fin heat sink. The non-uniform temperature distribution was attributed by the direction of inlet airflow, whereas the low temperature was found in the region that close to the inlet airflow. Thus, the research findings indicated the design of heat sink significantly affects the temperature distribution during the electronic cooling process.

Optimization and feasibility analysis of a microscale pin‐fins heat sink of an ultrahigh concentrating photovoltaic system

Nowadays, the most recent optical configuration based on Cassegrain and Fresnel lens designs of concentrator photovoltaic(CPV) has shown a race to achieve the ultrahigh concentration ratio. Still, none of those has experimentally shown an optical concentration ratio (GC) beyond 2000 suns. This is because their energy concentration ratios are challenged by the excessive temperature raised throughout the optical stages, which diminishes the efficiency of the solar cell. In this context, this research work aims to numerically investigate a microscale pin-fins heat sink configuration to enhance the thermal performance and the cost-competitivity of ultrahigh CPV thermal receiver. The impacts of the solar cell area, cell efficiency, and heat sink's material have been analyzed and discussed. The results showed that a circular pin-fins heat sink could accomplish a drop of 23.28% in the maximum operating cell temperature at 10 000 suns for cell area of 1 × 1 mm2 relatively compared to the conventional flat-plate heat sink. Furthermore, for a circular pin-fins heat sink with a cell area of 2 × 2 mm2, the cell temperature started exceeding the safe operating range of temperature (80°C) at 8000 suns with an average temperature of 96.1°C and reaching a maximum of 113.91°C at 10 000 suns. A gradient temperature on the planar direction of the aluminum circular pin-fins heat sink was about 1.187°C at 10 000 suns whereas 0.703°C was recorded in the case of a copper circular pin-fins heat sink. The circular pin-fins heat sink showed the highest thermal performance resulting in maintaining the solar cell temperature within its safe operating range even beyond 10 000 suns. From an economic point of view, aluminum circular pin-fins heat sink has been found to be less costly than the copper one. Finally, it was found that at 8000 suns, the flat-plate heat sink cost is more expensive than the traditional pin-fins heat sink by 14.7%, where the flat-plate heat sink becomes the worst economic configuration at 10 000 suns. At that concentration ratio, the cost has increased by 43.38%, 5.75%, and 10.61% compared to the traditional pin-fins heat sink, cylindrical pin-fins heat sink, and circular pin-fins heat sink, respectively.

Experimental investigation of heat transfer in pin-fins heat sinks for cooling applications

This study investigates the thermal performance of square pin-fin heat sinks for different operating conditions including different heat flux and different Reynolds numbers. Two heat sinks with different sizes of copper square pin-fins cross section (2-mm fins and 500-μm fins) in-line arranged are experimentally investigated to determine their thermal performance quantified in terms of thermal resistance. The investigation is carried out for a Reynolds numbers between 80 and 470, and heating rate between 21.9–46.7 W. The results indicate that the thermal resistance is lower for micrometer sized fins for smaller Reynolds number as compared to millimeter sized. However, for the larger Reynold numbers, thermal resistance of millimeter sized fins was observed to be lower. The fluid velocity plays a very important role in heat transfer, and it has more pronounced effect on the thermal resistance compared to the fins size.

Optimization of Pin Fin Heat Sink Using Taguchi Method - A Review

Optimization of Pin Fin Heat Sink Using Taguchi Method - A Review

Numerical Study of Heat Transfer for Gravity-Driven Particle Flow along a Vertical Oscillating Pin-Fin Plate

Nowadays, moving bed heat exchanger (MBHE) is being gradually applied in the fields of industrial waste heat recovery and solar energy utilization, due to its easy production of clean energy and low cost. However, the heat transfer performance of the MBHE is relatively poor. In the present paper, the heat transfer performance of gravity-driven particle flow in a pin-fin plate heat exchanger unit (PFPHEU) is numerically studied using discrete element method. The effects of pin-fin and plate oscillation on the heat transfer of gravity-driven particle flow along a vertical plate are carefully analyzed. The results show that, the heat transfer coefficient of the static PFPHEU is about 12.5 % less than that of the PWPF due to the higher porosity around the pin-fin compared to the plate without pin-fin (PWPF). The plate oscillation can significantly improve the particle filling rate around pin-fins and enhance the thermal dispersion of particle flow. The heat transfer in a PFPHEU is enhanced, and the heat transfer coefficient of PFPHEU increased by 87.6 % and 113.5 % compared with that of PWPF as the amplitude was 1 mm and 2 mm.

Electrical Circuit Modeling and Validation of Through-Silicon Vias Embedded in a Silicon Microfluidic Pin-Fin Heat Sink Filled With Deionized Water

This article presents the electrical circuit model of signal-ground through-silicon vias (TSVs) in a silicon microfluidic pin-fin heat sink in which the pin-fins are surrounded by deionized water. Such TSVs are asymmetric vertically because the TSVs are partially embedded in cylindrical pin-fins as well as in a rectangular silicon base. In this article, we propose a circuit model that segregates the asymmetric geometry into two symmetric segments: one segment for a silicon base and the other segment for cylindrical silicon pin-fins surrounded by deionized water, which we refer to as “a pin-fin segment.” Specifically, the pin-fin segment is modeled using two-dielectric coaxial-line formulas to represent the double layers of silicon dioxide and silicon that surround the copper vias. Using the developed circuit model, this article quantitatively analyzes the impact of fluidic designs, such as the diameter and height of pin-fins on the electrical characteristics of TSVs. Following circuit model validation using high-frequency electromagnetic field simulations, the modeling results are compared with measured data.