Pin Fin Heat Sink Research Articles

Thermal performance of center-cleared hollow cylindrical pin-fin heat sink for electronic cooling

Thermal performance of center-cleared hollow cylindrical pin-fin heat sink for electronic cooling

Comparative Analysis of Modular Pin-Fin Heat Sink Performance: Influence of Geometric Variation on Heat Transfer Characteristics

The advancement of digital technology in the age of Industrial Revolution 4.0 has driven other engineering sectors to keep up with the progressive demand for high-performance computing and electronics. Thermal management plays a critical role in maintaining the performance of electronic devices by keeping the system temperature at an optimal level and preventing overheating. A heat dissipation device widely employed in computing and other electronic systems’ heat management is a fin-type heat sink, owing to its robust and simple design. In this work, the authors evaluated heat sinks of different pin-fin cross-sectional geometry, arranged in a staggered configuration, in terms of heat transfer characteristics under forced convection. Three basic geometries were chosen on the grounds of manufacturing easiness and market availability: circular, square, and hexagonal. All the tested geometries had approximately the same hydraulic diameter. Therefore, the results could be compared to each other. The investigation revealed that the square cross-section induced an excellent convection coefficient, hence higher heat dissipation, compared to the counterparts. The tradeoff between heat transfer performance and size-related parameters, such as surface area and material volume, is also discussed in this paper.

Thermal and hydraulic performance of 3D printed jet impingement configuration for SiC power modules in aerospace propulsion inverters

Efficiently controlling the temperature of power electronic inverters is crucial for aerospace applications with high power density. Effective thermal management strategies could enhance the power output of power inverters to their maximum rated capacity. Jet impingement is a promising technology with outstanding heat transfer characteristics, making it a sophisticated aid for cooling innovation in power inverters. A numerical comparative study was conducted between jet impingement and traditional pin finned heat sink. In our case study, the pin fin could not effectively regulate the junction temperature to a level below 150 °C. By using a 3D printed jet impingement housing composed of polymer, the weight of the power module thermal management system could be decreased by 71 % compared to a metallic pin finned heat sink. Moreover, this approach aids in lowering the junction temperature to 129 °C, under the same boundary conditions. Additionally, a numerical study was conducted on power modules with thermal imbalance used in aerospace inverters. The study proposed various configurations of jet impingement to reduce temperature differences between power module switches, as well as minimize the pressure drop across the jet impingement housing. The primary objective is to minimize the temperature disparity between the unbalanced switches in order to improve the overall reliability and lifespan of the power module, while decreasing the pressure drop. Among all the options, the optimum design achieves a minimal temperature difference of 24 °C between the power module switches, while the pressure drop reaches 12 kPa.

A numerical investigation on the effect of shape-size-number of drills on heat transfer characteristics of a circular pin fin

An increased circuit density with digitalization and miniaturization demands a compact design for the heatsink with enhanced heat dissipation capabilities. The performance of an active air-cooled pin fin heatsink depends on the geometry of the fin, which should offer more surface area for the given volume (Compact). Providing drills in a pin fin offers a more convective surface with conduction loss, and is function of place, size, shape, and number of drills. So, this investigation is focused on studying the heat transfer characteristics of a drilled pin fin of length L and diameter D to elucidate the effect of (1) shapes; circular, elliptical, and triangular, (2) locations; L/4, L/2, and 3 L/4, (3) sizes between 0.3D and 0.5D, and (4) number; 1, 2, 4, and 6 of drills on maximum fin temperature (Tmax ) and convective resistance for differential heat inputs in different convection environments. It throws light on the possible replacement of solid fins with drilled fins for enhanced heat dissipation. It offers either more heat transfer, for the given volume with reduced weight, or decreased volume for the mandated heat load. The results demonstrated that the drill location has a mere or insignificant effect on Tmax. For all the shapes considered in the study, Tmax first decreases with the enlarging drill size reaches it’s minimum at 0.5D, and increases after that. The increased number of drills from 1 to 6, of size 0.5D, brings down the Tmax by 20%, 20%, and 25% with circular, elliptical, and triangular drills, respectively.

A novel case of honeycomb shaped pin fin heat sink: CFD-data driven machine learning models for thermal performance prediction

This research explores a useful thermal engineering application utilizing novel honeycomb-shaped pin fins heat sink (PFHS). 3D incompressible flow and heat transfer are examined using standard k-ԑ turbulence model for Reynolds numbers (Re) ranging from 8547 to 21367. Using the PFHS with 1.5 mm side length and pitch arrangement of (S =25 × 25), the Nusselt Number (Nu) increased by 171 % at a Re of 21367. Furthermore, Cu-Diamond composite material raises Hydrothermal performance factor (HTPF) to 3.304. At a Re of 8547, honeycomb heat sink has 200 % greater HTPF than the baseline. Predictive modeling of HTPF, Nu, and pressure drop (ΔP) was done using Artificial Neural Network (ANN), Multiple Linear Regression (MLR), Extreme Gradient Boosting Regression (XGBR), and Light Gradient Boosting Machine Regression (LGBMR). The four models with the highest R2 and lowest MRE on the test dataset performed best. Both models were implemented using Keras and Sklearn. XGBR and MLR have superior HTPF prediction accuracy (R2test = 0.977, MRE (%) = 1.1 and 0.924, MRE (%) = 2.1). XGBR and MLR predicted the Nu well with R2test values of 0.979 and MRE percentages of 1.9 and 3.9. R2test of 0.999 and MRE (%) of 0.3 indicate that XGBR predicts pressure reduction.

Extensive computational fluid dynamics analysis of microchannel flow topology and friction factor in arrays of conical pin-fins

The design of integrated circuits presents an increasing challenge for engineers, who seek to identify effective methods for cooling the miniature electronic components that are becoming increasingly complex. One potential solution is the use of micro pin-fin heat sinks, which have the potential to be an effective thermal management technique. This study compares the potential thermo-hydraulic efficiency of micro heat exchangers with conical pin-fins, arranged in two alternative patterns. The flow topology was investigated using the critical points theory and Ω-criteria to gain a deeper understanding of vortical structures and flow separation. 75 variations of pin-fin arrays were simulated and analyzed. It is noteworthy that no pattern similar to bidirectional pin-fins has been studied previously. The input datasets for the simulations included pitch/height ratios ranging from 0.823 to 1.235, cone angles from 0° to 13.48°, and flow Reynolds numbers of 40–117. The numerical results show that Ω and kinetic energies can predict the onset of instabilities. The degree of conicity and the pattern affect the friction factor, typically reducing it. The conical shape and arrangement of pin-fins can also aid in stabilizing the flow. Furthermore, the dependence of the friction factor on pitch/height and Reynolds was quantified with the calculated mean relative error of 1.7%. Moreover, turbulence parameters and friction factors were used to evaluate the thermohydraulic properties, deliberately excluding heat transfer simulations. This approach allows a much wider range of geometric modifications to be investigated for the preliminary optimization of the thermal and hydraulic performance of microchannels.

Enhancing solar thermoelectric power generation with supercritical CO2 cooling: Hydraulic, thermal, and exergy analysis

This research investigates the dynamic behavior and impact of various factors on the hydraulic, thermal, and exergetic characteristics of a solar-based thermoelectric device using a pin–fin heatsink cooled by supercritical CO2. A comprehensive numerical model analyzes the heat dissipation and performance of the power generator, integrating a thermoelectric generator and a pin–fin heatsink with various pin shapes. Key geometric and operational parameters, such as the height of PN (P-type and N-type semiconductor) legs of the TEG, the number of thermocouples, operating pressure, Reynolds number, and CO2 temperature, are examined for a comprehensive performance assessment. The study highlights the superior performance of CO2 coolant over traditional water-cooling system. Near the critical temperature of CO2, enhanced heat transfer significantly boosts power output, conversion efficiency, and exergetic efficiency. For example, at 8 MPa, the TEG’s (thermoelectric generator) power output increases from 1.31 mW at 295 K to 2.35 mW at 310 K. Comparisons reveal that while water coolant lowers the cold side temperature more effectively, it results in reduced power output due to decreased temperature differentials and increased pressure loss. Conversely, CO2 coolant maintains higher cold side temperatures while having advantages in power output. At 315 K, the cold side temperature with water is 315.7 K compared to 346.7 K with CO2. Increasing the number of thermocouples from 18 to 32 for a leg height of 1 mm leads to an approximate 102.3 % increase in voltage. Raising the PN leg height from 1 mm to 2 mm for an NTC of 50 results in a nearly 99.8 % increase in voltage. Lozenge-shaped fin produces a peak power output of 2.73 mW, while square fin generates 2.62 mW. This research underscores CO2’s potential as a high-performance coolant in solar thermoelectric applications, offering insights into optimizing system design for maximum efficiency.

Optimal height distribution design and experimental validation of pin-fin heat sink under natural convection based on dynamic surrogate model

Pin-fin heat sinks are widely employed to dissipate heat from power devices under natural convection conditions. To improve heat dissipation performance, optimization of the fin height distribution was conducted in this study. In order to enhance optimization efficiency, we propose a dynamic surrogate model that integrates machine learning, iteratively sampling and training until the convergence criterion is met. Compared with traditional surrogate models, the dynamic surrogate model significantly reduces the prediction error of the optimal result, proving more efficient and yielding superior outcomes with fewer samples. By optimizing the fin height distribution, the heat sink thermal resistance was minimized without increasing mass. Subsequently, an experimental bench was developed to compare the heat sink's total thermal resistance pre- and post-optimization under natural convection conditions. Experimental results demonstrate that within the input heat flux range of q = 500–1200 W/m2, the optimized heat sink's total thermal resistance is diminished by 6.08% to 8.01%, without any mass increment, which confirms the dynamic surrogate model's efficacy in natural convection scenarios. This study elucidates the design principles governing the height distribution of pin-fins of heat sinks under natural convection, and provides a significant insight for guiding the design of pin-fin heat sinks.

Experimental and numerical investigation on fluid flow and heat transfer behaviour of foam cladded pin fin heat sink

As technology advances, there is a growing demand for more efficient cooling solutions in electronics. Open-cell metal foams offer a unique solution, combining the strength of metals with the characteristics of foams, including being lightweight and having a high heat transfer area-to-volume ratio. Fully covering heatsinks with porous materials results in high pressure drop values, which is undesirable for electronics cooling. This study proposes a novel design that incorporates cladded aluminum foams on the pin fins within a heatsink. The hydrothermal performance of the proposed design is experimentally and numerically investigated. The results indicate that increasing the cladding thickness enhances heat transfer performance while increasing the pressure drop. For a heatsink with a pin fin diameter of 5 mm at the Reynolds number of 1121, the foam thickness of 5 mm depicts 46.5 % higher hydrothermal performance compared to a pin fin heatsink without porous while a fully porous covered heatsink depicts 38.9 % higher hydrothermal performance.

A gyroid TPMS heat sink for electronic cooling

The trend toward thinner and lighter electronic devices necessitates developing advanced thermal management solutions to address modern microprocessors’ escalating heat dissipation demands. This study introduces an advanced thermal solution incorporating a gyroid TPMS structure with remarkable physical properties for microprocessor cooling. Detailed investigations were conducted using a full-scale heat sink model to understand the inner geometric structure, flow, and heat transfer characteristics within a gyroid heat sink (GHS). The thermo-hydraulic performance of the GHS design was systematically assessed against that of a pinfin heat sink (PHS) across different porosities and flow rates. Both heat sinks were evaluated under non-uniform heating conditions, considering three heating schemes, each with eleven randomly distributed hotspots. The thermohydraulic performance was assessed by calculating temperature non-uniformity, thermal resistance, and pumping power. A correlation was established using the cell size and cell wall thickness of a unit cell of gyroid TPMS to calculate its hydraulic diameter. The analysis revealed that the enhanced thermal performance of the GHS design can be attributed to its intricate and convoluted flow structure, along with a significantly large heat transfer surface area. However, these same factors contribute to a notably high-pressure drop. Compared to the PHS design, the GHS design showed better thermal performance at all the selected porosities and flow rates, albeit with higher pumping powers. The GHS design showed improvement in the thermal performance as the porosity decreased. Investigation under heterogeneous heating conditions showed substantially lower temperatures at the hotspots in the GHS design, along with reduced temperature variation among them. The study’s findings provide valuable insight into the advantages and drawbacks of gyroid TPMS structure for their application in electronic cooling.

Experimental and Numerical Study of Conical-Shaped Pin Finned Heat Sink with PCM Material

Experimental and Numerical Study of Conical-Shaped Pin Finned Heat Sink with PCM Material

Comparative thermo-hydraulic analysis of periodic stepped open micro pin-fin heat sink

Comparative thermo-hydraulic analysis of periodic stepped open micro pin-fin heat sink

Further Development of a High Pulse-Energy LED at 4 kHz for Volumetric Particle Tracking Velocimetry and a Demonstration Using 32 Such LED Units

In 2022, we reported at the 20th Lisbon symposium on the development of 460 nm LED specifically designed for illumination in volumetric Particle Tracking Velocimetry (PTV). At that time, our pulsed LED unit emitted light with a 6 ◦ divergence beam and a top-hat power cross section, producing 20 µ s pulses at a 4 kHz repetition rate and a 0.15 mJ pulse energy. Since then, we have been improving the efficiency of this LED. Currently, our LED unit emits a beam with similar specifications but with a pulse energy up to 0.65 mJ , which is 4.3 times more than the previous LED unit. We improved the efficiency of the electrical driver by further decreasing the footprint of the SMD circuitry and by using higher quality electronic components. Additionally, we replaced the aluminium pin fin heat sink with a copper pin fin heat sink and we characterized the thermal dissipation. Using SolidWorks, we integrated the electric driver, the copper heat sink and the collimating optics into a compact mechanical casing. These improvements resulted in an LED unit with greater overall efficiency, a larger pulse energy and a volume footprint that is half the the size of the previous design. Furthermore, we constructed four batteries of these LEDs, with each battery containing eight LED units. Here, we report on our improvements to the LED unit and our considerations in its development. Additionally, we describe preliminary results of a 3D-PTV experiment with Helium Filled Soap Bubbles (HFSB), which were illuminated by the four LED batteries.

Numerical study on the synergistic effects of ultrasonic transducers and nano-enhanced phase change material in CPU thermal management

This study numerically investigates the effectiveness of concurrently applying nano-enhanced phase change material (NEPCM) and an ultrasonic field for the thermal management of a pin fin heat sink. The role of the NEPCM is to absorb heat from the heat sink wall, while the ultrasonic field generated by ultrasonic transducers facilitates the accelerated melting of the NEPCM. The study investigated how varying the number of ultrasonic transducers positioned near each side wall of the square cross-section heat sink, along with adjusting the concentration of nanoparticles in the NEPCM, impacts the heat sink's performance. The total power consumption of the transducers is assumed to be constant and an increase in their number is associated with a decrease in the power consumption of each transducer. It was observed that raising the number of transducers and lowering the nanoparticle concentration both contributed to a decrease in the CPU's highest temperature. Additionally, it was found that by using the combination of ultrasonic field and NEPCM, the average temperature of CPU can be reduced by 12.33–15.91 °C to the case without the ultrasonic field. Moreover, raising the number of transducers and lowering the nanoparticle concentration both contributed to a decrease in the CPU's average temperature.

Multi-objective topology optimization design of silicon carbide metal oxide semiconductor field effect transistors power module liquid-cooled heatsink for electric vehicles

Silicon carbide (SiC) metal oxide semiconductor field effect transistors (MOSFETs) is gradually replacing silicon-based insulated gate bipolar transistor (IGBT) as the switching devices in electric vehicle power inverters due to its higher operating temperatures, switching speeds, and frequencyies. However, the high switching frequency of SiC MOSFETs can increase the losses of the power inverter, resulting in an increase in the temperature, which will limit the performance of power inverters. The improvement of power module performance is mainly controlled by optimizing its control methods during operation and improving its cooling system. Currently, the liquid-cooled heatsink used in power modules have disadvantages such as large flow resistance and poor heat dissipation performance. In order to enhance the performance of the heatsink, this study first established a three-dimensional finite element model of SiC MOSFETs power module based on a pin fin heatsink. The accuracy of the model was verified by numerical and experimental methods. Secondly, based on numerical analysis, a multi-objective topology optimization method for the power module liquid-cooled heatsink is proposed. This method takes heat exchange and fluid dissipation energy as the objective function and uses weight factors to adjust the influence of each on the objective functions. Additionally, the temperature distribution of the heatsink is considered to optimize its performance. Finally, the numerical results show that the topology-optimized heatsink exhibits better performance at high coolant volumetric flow rates. When the coolant volumetric flow rate is 14 L/min, the pressure drops of topology-optimized heatsink is reduced by 63.94 % and the junction temperature of the power module is reduced by 0.24 % compared with the pin fin heatsink. This topologically optimized heatsink could be helpful to improve the performance of existing power module heatsinks.

Evaluation of innovative thermal performance augmentation techniques in heat sinks & heat pipes: Electronics & renewable energy applications

Heat sinks and heat pipes have vast applications including industrial domains requiring high heat flux. Due to numerous uses of these heat transfer devices, there have been great advancement in this area through innovation. This study focuses use of nanofluids and hybrid nanofluids for thermal performance enhancement of heat pipes and heat sinks. There are five different arrangements finless sintered copper wicked heat pipe, water based TiO2 filled heat pipe, TiO2 and SiO2 based hybrid nanofluid filled heat pipe, water cooled cylindrical pin finned heat sink and Fe2O3 and TiO2 hybrid nanofluid cooled heat sink. There are two test rigs one for testing heat pipe configurations and other for heat sinks. All the five elements are tested at constant heat flux ranging from 900 W/m2 to 3600 W/m2, in four equal steps. It’s observed that nanofluids play a very significant role in thermal performance augmentation, the affect is even more significant in heat pipes compared to heat sinks. Interestingly, nanofluids based heat pipes are proved more significant for high heat flux applications, although, nanofluid cooled heat sinks have slight better performance compared to the said but at a higher expense of weight, auxiliaries, space and cost. At 3600 W/m2 nanofluid based heat pipes have 33 % lower thermal resistance compared to water cooled heat sink. Therefore, nanofluid based heat pipes are primarily significant unless use of heat sink deemed dire. Nusselt number of heat sink is calculated at various heat flux and at variable mass flux conditions and found increasing with both parameter.

Thermal and energy performance characteristics of spiral-wing pin-fin heatsinks for liquid cooling of electronic devices in electric vehicles

Insulated gate bipolar transistors (IGBTs) are crucial components of electric vehicles (EVs) that regulate power. Liquid cooling has emerged as a cooling solution for high-power IGBTs in EVs. Although several pin-fin heatsinks (PFHs) have been developed to enhance cooling performance, comprehensive research on PFHs for IGBTs under liquid-cooling conditions is limited. This study investigated the cooling performance improvement of spiral-wing pin-fin heatsinks (SWPFHs) against conventional PFHs under liquid-cooling conditions. Using the developed simulation model, the optimal design of the SWPFH was determined to achieve the maximum Webb efficiency, which indicates the heat transfer capacity at the same power consumption. Furthermore, the heat transfer performance of the optimized SWPFH was compared with those of conventional PFHs with circular, square, and hexagonal pin-fin heatsinks under practical Reynolds numbers. The optimized SWPFH exhibited the lowest maximum temperature and standard temperature deviation among the conventional PFHs. The Webb efficiency of the optimized SWPFH was 21.9% higher on average than that of the conventional circular pin-fin heatsink (CPFH) owing to the enhanced mixing effects with the reduced wake region. Overall, the use of SWPFH for cooling IGBTs in EVs is recommended to improve the thermal performance of the CPFH under the same pumping power.

Study on the flow boiling characteristics of novel pin fin heat sinks in a two-phase mechanically pumped cooling loop

As a new thermal control technology, a two-phase mechanically pumped cooling loop (MPCL) holds promise in addressing cooling issues of avionics. The heat sinks in MPCL can remove heat from avionics to refrigerant. Since previous research focused primarily on conventional heat sinks, three novel pin fin heat sinks (PFHSs) were investigated based on an MPCL. With increasing heat flux, heat transfer coefficient (HTC) and frictional pressure drop (FPD) increase. With the inlet state from subcooled to saturated and then to two-phase, HTC and FPD increase. Increasing inlet saturation temperature yields an increase in HTC and heating wall temperature (Tw). An increase in flow rate inhibits heat transfer deterioration while inducing significant growth in FPD. When heat flux is below 150 kW/m2, the petaloid I PFHS has the best temperature control performance, while the honeycombed PFHS has the best FPD. When heat flux exceeds 150 kW/m2, HTC decreases rapidly after reaching the peak. Increasing average vapor quality leads to a slight decrease in Tw but an increase in FPD. When heating load is started, flow rate decreases and Tw and pressure drop increase significantly, but they can gradually stabilize. These findings have significant implications for optimizing the MPCL.

Orientation effects on mixed convective performance of twisted pin fin heat sink: Experimental investigation

In the current work, an experimental study is carried out to examine the heat transfer performance and friction effects on a pin fin matrix of a heat sink for different design variables and operating conditions. This examination aims to assess the thermo-hydraulic performance of the heat sink with three orientations (90°, 180°, and 270°). In the presence of three heat loads (66 W, 91 W, and 121 W), each of these orientations is tested with three twisting angles (30°, 60°, and 90°) for different pin fins cross-sections of square and hexagonal at various ranges of air Reynolds number (Re) (3182 to 9971). The downward position of a heat sink achieves a higher Nusselt number (Nu) than the sideward and upward positions. The fin pin with a twisting angle 30° has superior efficiency for three orientation angles and hexagonal and square cross sections. Square pin fin records the lower thermal performance at Re = 3182, orientation angle (β) = 270˚, and pin twist angle (θ) = 30°, and the best at Re = 9971, β = 180°, and θ = 90°. Compared to 60˚ and 90˚, the pin fins had a reduced pressure loss at a twisting angle of 30°.

Experimental and Numerical Investigation of Single-Phase Liquid Cooling for Heterogeneous Integration Multichip Module

Abstract The variety of new electronic packaging technologies has grown significantly over the last 20 years as a result of market demands for higher device performance at lower costs and in less space. Those demands have pushed for heterogeneous packaging, where computer chips with different stack heights are closely packed, creating nonuniform heat flux and temperature and additional challenges for thermal management. Without implementing an appropriate thermal management strategy for heterogeneous packages, large temperature gradients can be observed within the package, which would increase the thermal stresses on the chip and raise reliability issues. To mimic this real-life scenario of such packaging, an experimental setup was designed and built. The design of the new experimental setup consists of four identical 1.2 cm × 1.2 cm ceramic heaters, each of which is connected to a separate power supply and can reach a heat flux of 140 W/cm2. Accordingly, this mock package is capable of delivering different power levels to mimic different multicore microprocessor conditions. To give the heater the ability to move precisely in the x-, y-, and z-directions, each heater is mounted to an XYZ linear stage. Deionized water (DI) was used as the working fluid, and a pin-fin heat sink was used to run the initial steady-state tests on the experimental rig. The tests showed how different flow rates at a constant fluid temperature and input power affect the temperatures of the heaters and the thermohydraulic performance of the heat sink. In addition, a three-dimensional numerical model has been developed and validated with experimental data in terms of heat sink pressure drop and the temperatures of the heaters.