Heat Sink Geometry Research Articles

Additive manufacturing-assisted casting of 3D micro-architected heat sinks

The rapid advancement in electronic devices has heightened thermal management challenges. This study presents the fabrication of 3D micro-architected heatsinks using additive manufacturing (AM) assisted casting. This approach merges AM’s design flexibility with casting’s cost-effectiveness and versatility, enabling complex heatsink geometries. The fabricated heatsinks were analyzed using scanning electron microscopy and computed tomography. The thermal behavior of the heatsinks was assessed in forced convection conditions. A temperature drop at the base ranging from 5% to 13% was measured.

A Multivariable Numerical Investigation of Wavy-Based Microchannel Heat Sink Geometry Towards Optimal Thermal Performance

Abstract This research provides a comprehensive multivariable comparative investigation of the effect of various microchannel configurations on their thermal performance. Three-dimensional fluid flow and heat transfer simulations are performed with different arrangements of the channel's width tapering and cross-sectional aspect ratio with an emphasis on the synergistic proven effects of geometrical parameters in innovatory combinations. Results confirm that wavy channels are significantly superior to straight channels in terms of thermal performance due to the creation of secondary flow (Dean Vortices), which improves the processes of advective mixing and, therefore, overall heat transfer characteristics with minimal pumping power penalty. Width-tapering of wavy channels also shows better thermal resistance than untapered wavy channels producing almost 10 percent thermal resistance improvement. The study indicates a significant dependency of thermal performance on the cross-sectional aspect ratio of the channel which suggests that there are ideal tapering and aspect ratio conditions. An innovative wavy-tapered microchannel heat sink has been introduced, featuring an optimal parametric configuration and directionally alternating coolant flow. This design results in additional thermal resistance improvement by 15% and significantly improves substrate temperature distribution uniformity. Overall, the results demonstrate the superior potential of the configuration for high-end electronics cooling tasks. These results provide interpretive insight into microchannel heat sink design and optimization.

PARTICLE SWARM OPTIMIZATION AND CFD ANALYSIS OF A HEAT SINK FOR FORCED CONVECTIVE COOLING OF A DC/AC INVERTER

Power inverters play a crucial role in converting DC voltage and current to AC voltage and current. Its efficient operation relies on effective thermal management of the semiconductor devices, such as the IRF 3205 MOSFET chip which facilitate the switching operations to prevent thermo-mechanical stress that could to failure. This research developed and optimize a heat sink for an IRF 3205 MOSFET chip in a 3.5 KVA power inverter, using the Particle Swarm Optimization technique and experimented with a 3.5 KVA 24 V power inverter operating a 1.5HP air-conditioning unit. The heat sink geometry has 26 fins, 4 mm fin thickness, 40 mm fin height, 3 mm fin spacing, 2 mm fin base thickness, 179 mm length, 80 mm width and a thermal resistance of 60.75 °C/W. The thermal performance was evaluated using ANSYS Computational Fluid Dynamics (CFD) and results showed maximum base temperature of 65.85°C and experimental temperature of 64°C after two hours of steady operation dissipating heat of 45W. The results from both numerical and experimental data demonstrate the effectiveness of the optimized heat sink in maintaining the chip's temperature below its maximum working threshold of 170°C.

MODELING THERMAL BEHAVIOR IN HIGH-POWER SEMICONDUCTOR DEVICES USING THE MODIFIED OHM’S LAW

This paper addresses the challenge of thermal management in high-power semiconductor devices, where increasing power densities and complex operating environments demand more accurate thermal prediction methods. Traditional approaches often rely on simplified models that do not account for the crucial factor of temperature-dependent resistance variations. This limitation leads to inaccurate device temperature predictions, potentially compromising device reliability. This work proposes a novel approach for thermal management by introducing the first empirical application of a Modified Ohm’s Law. This modified law incorporates an exponential term to account for the non-linear relationship between temperature, current, and resistance. The paper demonstrates through simulations and empirical validation that the Modified Ohm’s Law offers a more accurate representation of thermal behavior compared to the standard version. This translates to more precise predictions of device temperature, especially during periods of rapid temperature changes. The validation process goes beyond simply establishing the Modified Ohm’s Law. It provides valuable insights into the thermal dynamics of the device, allowing for the refinement of simulation parameters used to assess various cooling strategies. These strategies include simulating different heat sink geometries and materials, modifying airflow rates over the device’s surface, and exploring the impact of Thermal Interface Materials (TIMs) between the device and the heat sink. By incorporating these elements, the simulations provide a more comprehensive picture of the device’s thermal behavior under various operating conditions and cooling configurations. Ultimately, this paper not only advances the theoretical understanding of thermal management but also offers practical benefits. Through enabling more accurate thermal predictions, the Modified Ohm’s Law model paves the way for informed decision-making in device design and optimization.

Evaluation of thermal performance and vibration effects on automotive headlights for selection of heat sink geometry

Evaluation of thermal performance and vibration effects on automotive headlights for selection of heat sink geometry

Heat transfer optimisation using novel biomorphic pin-fin heat sinks: An integrated approach via design for manufacturing, numerical simulation, and machine learning

With the availability of advanced manufacturing techniques, non-conventional shapes and bio-inspired/biomorphic designs have shown to provide more efficient heat transfer. Consequently, this research investigates the heat transfer performance and fluid flow characteristics of novel biomorphic scutoid pin fins with varying volumes and top geometries. Numerical simulations were conducted using four hybrid designs for Reynolds Number 5500–13500. The impact of pin fin 'top' geometrical features on the heat transfer coefficient (HTC) was evaluated by combining computational fluid dynamics (CFD), experimental data, and machine learning. The results highlighted that the new pin fins saved 6.3 % to 14.3 % volume/material usage but produced around 1.5 to 1.7 times more heat transfer than conventional square/rectangular fins. Also, manipulating pin fins via the top geometrical properties can lead to more uniform velocity and temperature distributions while demonstrating the potential for increased thermal efficiency with reduced thermal resistance. Furthermore, six machine learning models accurately predict HTC using volume and surface area as key variables, achieving less than 5 % mean absolute percentage error (MAPE). Overall, this research introduces innovative biomorphic designs with unconventional geometries, emphasising resource optimisation and efficient HTC prediction using machine learning. It simplifies design processes, supports agile product development, calls for re-evaluation of conventional heat sink geometries, and provides promising directions for future research.

Numerical investigation of thermal and hydraulic characteristics in porous pin fin heat sinks using single phase nanofluids

This study aims to numerically investigate the thermal performance of porous square pin-fin heat sinks, considering three different configurations: inline, staggered, and 45° inline. Six different nanofluids, comprising CuO, Al2O3, and TiO2 nanoparticles dispersed in water and water–ethylene glycol mixtures at two volume fractions (φ = 0.5 % and 2 %), are employed as coolants. The impact of porosity on the thermal and fluidic behavior is also examined for the CuO–Water nanofluid (φ = 2 %) at porosity values of 40 %, 50 %, and 60 %. The commercial CFD code: Ansys Fluent 2020R1 is utilized for this numerical analysis and the results are compared to relevant experimental works for validation. The effects of heat sink geometry, nanofluid type, and porosity on heat transfer performance are systematically analyzed. The results show that the 45° inline configuration of the square pin-fin heat sink exhibits superior heat transfer enhancement compared to both the inline and staggered configurations. The use of nanofluids as coolants significantly improves the thermal performance compared to conventional fluids, with CuO–Water nanofluid demonstrating the most promising results. This comprehensive analysis provides valuable insights for the design optimization of high-performance cooling systems for electronic devices.

GENERALIZED THERMAL OPTIMIZATION METHOD FOR THE PLATE-FIN HEAT SINKS OF HIGH LUMEN LIGHT EMITTING DIODE ARRAYS

The performance of high-lumen light-emitting diode (LED) arrays is strongly affected by high temperatures. For better performance, the design of better thermal management techniques is required. In this work, an analytical thermal optimization algorithm for the passive heat sinks of high-lumen LED arrays is presented. With the aid of this algorithm, a broader range of heat sink geometry alternatives can be explored for the identification of the optimal heat sink design. This task is challenging using experimental or numerical techniques. The results demonstrate that the algorithm yields design with a reduction of more than 30% in base temperatures compared to previous heat sink design studies when minimum mass and maximum total efficiency constraints are applied. For devices with high powers, small chip spacing, and space limitations in the horizontal axis where base temperatures cannot be further reduced using these constraints, minimum temperature optimization can result in up to a 17% reduction in base temperatures. This reduction in base temperatures significantly improves the junction temperatures and the overall lighting quality of the LEDs.

Performance enhancement of topology-optimized liquid-cooled heat sink with increased spanwise length of design domain

Topology optimization generate promising ‘heat sink fin layouts’ to satisfy the thermo-hydraulic objectives with lightweight designs. This article evaluates the performance of topology-optimized liquid-cooled heat sinks with different spanwise length-based design domains. A reduced-scale model (with 1/8th the width of the full-scale heat sink model) is selected and optimized with ‘pressure drop’ and ‘average junction temperature’ as objective functions and constraints, respectively. Fin layouts consisting of non-continuous fins are derived for different inlet flow velocities and temperature constraints using an accurate two-dimensional (2D) mathematical model, mimicking a three-dimensional (3D) heat sink geometry. Three-dimensional CFD simulation is used to compare the performance of the present fin layout with a reference topology-optimized design (with 1/16th the width of the full-scale model) and an augmented straight channel-based heat sink. To cool the heat sink to an average junction temperature of 50 °C, the present design requires 17 % and 54 % lower pumping power compared to the reference design and straight channel with significantly reduced material volume. Flow phenomena such as secondary flow-induced mixing and frequent reinitialization of boundary layers at leading edges of fins are observed during numerical investigation which are illustrated using velocity and temperature contours. The optimized fin layout's overall performance is compared with existing fin designs of heat sinks such as step fins, offset strip fins, oblique fins, and oblique and trapezoidal fins. Oblique and trapezoidal fin and oblique fin compete with topology optimized design which outperforms at lower flow rates (for velocity ranging from 0.05 m/s to 0.175 m/s). The average junction temperature using Oblique and trapezoidal fins and oblique fins are 63 °C and 61.22 °C, respectively compared to 58.5 °C for topology-optimized design with a similar pressure drop of 300 Pa.

Thermal management with double layered heat sink produced by direct metal laser sintering

In this study, the thermal management of a heat sink which is the heart of a cold plate is investigated considering Additive Manufacturing (AM) technology. Although AM enables many flexibilities, it also brings some limits to design and manufacturing. In general, a cold plate is developed to cool many heat sources with an appropriate heat sink design just under the sources to have a maximum cooling rate. Due to the nature of Direct Metal Laser Sintering (DMLS) AM technology, we have to use some supports (used as pin fins in this study) to avoid material collapse to have a rugged and fine product. In this study, straight rectangular channels with the production limit of AM technologies have been investigated in detail and the results are compared to investigate the heat treatment effect for the same design. Due to its cooling advantages in a confined space, a double-layered heat sink is chosen as the heat sink geometry to reach the goals. In order to succeed in electronic performance requirements, two heat sources on each side of the plate (heat sink) must be so cooled that their temperatures are close to each other. This is one of the requirements in radar electronics to have higher performance and to decrease the necessary calibration efforts. Deliberately, the heat load is selected as 100W/cm2 using mini or smaller channel sizes to enforce the limits of AM technology. One of the most important aspects of a cold plate design is to distribute the fluid to the heat sources to collect it properly without sacrificing electronic components and use the space effectively. As a result; The Double Layered Heat Sink design allows temperature difference between the heat sources to be kept around 1°C with 100W/cm2 heat flux.

Optimization of Heat Sink Geometry for Improved Thermoelectric Generator Efficiency

Optimization of Heat Sink Geometry for Improved Thermoelectric Generator Efficiency

Numerical study and optimization of thermal efficiency for a pin fin heatsink with nanofluid flow by modifying heatsink geometry

This paper presents a numerical study on the thermal efficiency of a pin fin heatsink (HEK). The working fluid used is an alumina/water nanofluid, which enters the HEK in a laminar flow regime and exits from its surroundings. This study involves varying the distance between circular pin fins, their height, and their diameter. By altering these parameters, we determine the values of thermal resistance (THR) and temperature uniformity (Teta) on the HEK, along with the heat transfer coefficient (HTC). We further optimize the obtained results using artificial intelligence techniques to minimize the THR of the HEK, maximize the HTC, and achieve the best Teta on the HEK. This numerical investigation employs a two-phase approach to model nanofluid flow within the HEK. The optimization process yields predictions with an accuracy of less than 4%. The findings reveal that increasing the height of the pin fins reduces the HTC and the heat capacity of the HEK, while simultaneously improving the Teta on the HEK. Expanding the distance between pin fins enhances the HTC, decreases the THR of the HEK, and further improves the Teta on the HEK. Similarly, augmenting the diameter of the pin fins amplifies the HTC, reduces the THR, and enhances the Teta on the HEK.

Thermal management of honeycomb heat sink filled with phase change material for smart lighting applications

Recently, thermal management of LEDs lamps has become increasingly essential due to the widespread integration of LEDs in smart lighting applications. In this work, we focus on the thermal analysis of convective heat transfer using a honeycomb heat sink designed for LEDs lamp cooling. Three different heat sink geometries were examined: an aluminum-filled honeycomb radiator, a hollow honeycomb radiator, and a hollow honeycomb radiator incorporating a phase change material (PCM) layer. The results obtained from numerical simulations using COMSOL Multiphysics® showed that the third heat sink geometry, when employed in short-duration lighting applications, led to a 25% reduction in temperature for a 20W power lamp. We also determined the optimal operational time, during which the temperature drop is maximum. Moreover, we observed that the integration of a PCM-filled honeycomb radiator in cyclic lighting applications (involving on/off cycles and high/low power settings) significantly mitigates temperature rise in the lamp by leveraging the PCM's heat storage capacity. This approach effectively prevents thermal shocks, ensures prolonged LEDs performance, and contributes to energy savings in the lighting sector. By addressing the thermal management challenges associated with LEDs lamps through innovative heat sink designs and the utilization of PCM, our research offers valuable insights for enhancing the overall performance and efficiency of LED lighting systems.

OPTIMIZATION OF FINNED HEAT SINKS WITH ELECTROSPRAY COOLING: FULL FACTORIAL METHOD

In this study, the optimum heat sink geometry was determined by the full factorial method with electrospray cooling, which has started to find a place among the methods used for the removal of high heat flux in recent years. The experiments were carried out at 4.4 kV voltage, 0.2 mL/min flow rate, d<sub>i</sub>= 0.61 mm nozzle diameter, and 20 mm nozzle-to-heat sink distance. Ethanol was used as the cooling fluid. The experiments were carried out in the cone jet electrospray mode. As a result of the experiments performed with square, rectangular, and triangular fin heat sinks, it was determined that the best cooling performance was achieved in the square fin heat sink. As a result of the experiments carried out with the square fin heat sink with 27 different geometries, it was determined that the most effective cooling was achieved in the Square-18 heat sink with 3 mm fin width, 3 mm fin distance, and 3 mm fin height. An average temperature value of 51°C and a fin enhancement ratio of 1.11 were obtained for eight different heat fluxes (3.2-2.99-2.75-2.59-2.4-2.19-2.02-1.88 kW/m<sup>2</sup>) in the Square-18 heat sink.

HORIZONTAL SINUSOIDAL WAVY FORM PLATE-FIN HEAT SINKS FOR NATURAL CONVECTION HEAT DISSIPATION

The plate-fin heat sink geometry was modified to have the fin form sinusoidal wave shape in the horizontal direction with twelve variations by amplitude and period changes. Three different wave periods and four different wave amplitudes were used. The purpose was to alter natural convection motion in favor of heat transfer effectiveness. The main performance indicator was the base-plate average temperature. The independent geometric parameters were experimentally examined in terms of the effectiveness of natural convection heat transfer by the measured average temperature values. Heat transfer by radiation was calculated by an analytical algebraic approach in order to obtain the Nusselt number solely based on convective heat transfer. Eight different heat inputs were used for each tested geometry to change the Grashof and Rayleigh numbers in a laminar flow interval. As reference geometries, a flat plate and a heat sink with straight/flat-plate fins were utilized. The heat sinks were also oriented to three different angles by a test stand. Accordingly, thirty six unique experimental cases were examined as a result of 327 trials and 1100 hours of testing. It was realized that the wavy fin geometry enhances natural convection heat transfer compared to the base-plate and flat-plate-fin heat sinks. However, increasing period and amplitude of the wave form more than initial values deteriorated the gains by the modifications on the fins. Since a single-period, 2-mm-amplitude heat sink resulted in the highest Nusselt number for all orientations, an optimum may be sought about this setting. As a general evaluation, computational simulations for spatial resolution of the event physics and dimensional optimization are standing as future study targets.

Automotive Silicon Carbide Power Module Cooling With a Novel Modular Manifold and Embedded Heat Sink

Abstract The next generation of integrated power electronics packages will implement wide-bandgap devices with ultrahigh device heat fluxes. Although jet impingement has received attention for power electronics thermal management, it is not used in commercial electric vehicles (EVs) because of the associated pressure drop and reliability concerns. In this paper, we present a modular thermal management system designed for automotive power electronics. The system achieves superior thermal performance to benchmarked EVs while adhering to reliability standards and with low pumping power. The system utilizes a low-cost and lightweight plastic manifold to generate jets over an optimized heat sink, which is embedded in the direct-bonded-copper (DBC) substrate. The embedded heat sink concept leverages additive manufacturing to add elliptical pin fins to the DBC substrate. The heat sink geometry is optimized for submerged jet impingement using a unit-cell model and an exhaustive search algorithm. The model predictions are validated using unit-cell experiments. A full-scale power module model is then used to compare the DBC-embedded heat sink against direct DBC cooling and baseplate-integrated heat sinks for single-sided (SS) and double-sided (DS) cooling concepts. Using the SS and DS DBC-embedded cooling concepts, the models predict a thermal resistance that represents a reduction of 75% and 85% compared to the 2015 BMW i3, respectively, for the same water-ethylene glycol inverter flowrate. We have shown that an inverter with a 100-kilo-Watt-per-liter power density is achievable with the proposed design.

Multi-objective reduced-order design optimization of single-phase liquid coolers for electronics

Thermal management using liquid cooled cold plates is a key enabler in modern electronic systems such as power converters and multi-chip arrays. Traditional cold plate designs are limited in their ability to handle the heterogeneous heat profiles in ever-larger modern multi-chip arrays requiring design optimization. This work demonstrates a design optimization method for liquid-cooled cold plates subjected to discrete heat dissipation profiles. We used reduced order performance modeling enabled by splitting the heat sink geometry onto a coarse grid with up to 50 elements each assigned with a simplified flow block such as a straight, elbow, or tee section. Correlations for thermal-fluidic performance metrics were used to obtain the pressure drop and surface temperature. Multi-objective design optimization focused on minimizing the pressure drop and temperature was broken down into layout and geometry optimization sub-steps. Layout optimization found the optimal flow path from inlet to outlet using a novel optimal path search method combining pathfinding algorithms with search on a random population. Geometry optimization solved for the dimensions of the coarse grid elements and the corresponding flow blocks using gradient based optimizers. We experimentally tested an aluminum water-cooled heat sink design generated by the reduced order optimization demonstrating a thermal resistance of 0.065 K/W. We compared the performance of our optimal designs with conventional and topology optimized cold plate designs to benchmark performance, computational cost, and computational time. Topology optimized designs showed a 22% reduction in average heated surface temperature for similar pressure drops. However, the computation time required to generate the topology optimized design was more than one order of magnitude higher than the reduced order method, requiring over 3,600 s to generate the optimal design. Our reduced order optimization in comparison provides optimal designs at computational timescales of 60 s.

Design of PCM-based heat sinks through topology optimization

Ever-increasing heat fluxes of electronic components ask for higher performance of devices responsible for their cooling. Against that background, PCM-based heat sinks – because of their compactness, and effectiveness – are well-established solutions for thermal management issues. Even though solutions for the thermal enhancement of PCM devices have been widely presented, new ways to optimize such systems are emerging. Among them, this work investigates the application of density-based topology optimization to define innovative heat sinks design able to minimize thermal resistance under constant wall temperature. A 2D numerical model is developed by means of a finite element tool. The heat equation is solved for the topology optimization problem with the objective of minimizing the average temperature, considering further manufacturing restrictions. Solid-isotropic-material-with-penalization (SIMP) method is applied to link the design variable to material properties. Parameterization of Helmholtz filter’s minimum feature size and projection based on the hyperbolic tangent function is performed, showing improved performance as well as feature size decrease. The optimized prototype – with PCM – is then simulated with the enthalpy-porosity model to assess the benefits, i.e., reduction in the melting time, with respect to the baseline. Results show the potential of optimizing heat sinks via a topology-based approach and confirm it as a promising tool for finding new heat sink geometry, whatever the application.

Thermal and fluid dynamic optimization of a CPV-T receiver for solar co-generation applications: Numerical modelling and experimental validation

Solar co-generation, i.e., the generation of electricity and heat in a single device by concentrating the sunbeams, has the potential to significantly increase the overall system performance. The main challenge is related to the cooling of solar cells. In order to do so, it is essential to reduce the thermal resistance between the cell and heat transfer fluid. This paper features the optimization procedure of a low-cost custom concentrated photovoltaic thermal (CPV-T) receiver for a parabolic trough collector using silicon solar cells. A finite volume model for the thermal process has been developed. Hence, a fluid dynamic thermal simulation of the receiver is presented. The optimized heat sink tube geometries have been manufactured and tested in a lab environment, allowing for a comparison between modelling and experimental test results. Three possible heat sink geometries have been designed and compared regarding their overall heat transfer coefficient with respect to the non-dimensional pumping power, i.e. the ratio between the overall transferred heat and the energy required for pumping. The overall heat transfer coefficient for a finned heat sink has been increased up to 60% with respect to a baseline case without fins under similar conditions.

Machine Learning-Based Optimization of a Mini-Channel Heatsink Geometry

Machine Learning-Based Optimization of a Mini-Channel Heatsink Geometry