Optimization Of Heat Sink Research Articles

Architected materials informatics: Construction and application to cellular-structured heat sink optimization

Architected materials informatics: Construction and application to cellular-structured heat sink optimization

Fin angles optimization of water-cooled plate-fin heat sink based on anisotropic Darcy–Forchheimer theory

Flat heat sinks are devices for efficient heat dissipation and are important components in manufacturing. For example, in precision glass molding, it is utilized as a cooling plate contributing to improve the quality of the product by reducing residual stress and shape deviation, during the gradual cooling phase. In this study, we attempted to achieve precise temperature design of the cooling plate using variable lattice optimization. Fins allow for controlling the flow direction and achieving efficient heat transfer. Therefore, elliptical cylindrical fins were adopted as lattice unit cells, increasing the design freedom of the flow field. To account for the asymmetric flow field within the unit cell, we introduced an asymmetric tensor for the coefficients of the effective physical properties in the Darcy–Forchheimer equation. The proposed method's effectiveness and validity are discussed through numerical calculations with effective material properties, reproduced detailed shapes, and experimental verification. The optimization aiming to minimize the average temperature yielded a numerical simulation temperature decrease of 24.6 % and an experimental temperature decrease of 14.1 % compared to the benchmark model.

Micro-Channel Cooling of Hot Spots Through Non-Uniform Aspect Ratio Designs

Abstract Electronic devices experience spatial variation in power dissipation, which results in high-temperature hot spots. These locations require aggressive thermal management, which can be complex and costly. Simple solutions such as single-phase micro-channels can provide adequate heat transfer, but they are not designed to control heat transfer locally. However, micro-channels can be tailored to control local flow rates and heat transfer, potentially mitigating hot spot temperatures. Using a conductive and convective resistance network for a micro-channel, an analytical model is generated for heat transfer within an individual passage. For a given channel width, this model relates the channel depth to its resistance through a power law. Over a wide range of heat fluxes, the optimal design balances local temperatures to within 3 K. The analytical model is validated using computational simulations of the optimized heat sink. For a randomly-generated, non-uniform power distribution, device temperatures are balanced with a sample standard deviation below 2.5%, which is significantly better than a baseline design. When heat spreading is incorporated, the temperature increase is smaller but remains uniform, indicating that the hot spots can be mitigated.

Electrohydrodynamic characteristics in parallel-fin channels and enhanced heat transfer performance of an ionic wind heat sink

High heat flux density may lead to a decline in the performance of highly integrated electronic components, which presents a major challenge to thermal management strategies. This work developed ionic wind heat sinks with parallel-fin channels for cooling high-power chips. The study examined the effects of intake air velocity, number of electrodes, and discharge spacing on the distribution of ionic wind flow and the improved heat transfer performance of the ionic wind heat sink. The findings suggest that the ionic wind heat sink with wire electrodes perpendicular to the fin channels can withstand higher operating voltages and generate more reliable corona discharges. The improved heat transfer capabilities are achieved with reduced inlet air velocity. The heat transfer enhancement factor (HTEF) of the ionic wind heat sink decreases as the discharge spacing increases, leading to a reduction in the peak value of the body force. The heat transfer capacity declines as the number of wire electrodes increases, because marginal effects lessen disruption to the thermal boundary layer. An effective airflow is achieved when wire electrodes are positioned upstream of the heat sink and run parallel to the fins, ensuring a steady and efficient cooling process. The design effectively disrupts the thermal boundary layer, reducing momentum loss in the flow and increasing the HTEF value by 21.2%. This improvement significantly enhances the heat dissipation capacity. The structurally optimized heat sink demonstrates excellent overall performance and is a viable option for improving heat dissipation in electronic devices.

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.

A computational search for the optimal microelectronic heat sink using ANSYS Icepak

The efficient thermal management of microelectronic devices is crucial for their reliability and performance. Heat sinks, particularly those with inline and staggered fin arrangements, are vital in achieving this goal. This study leverages the advancements in computational fluid dynamics (CFD) software to explore the optimal heat sink design for microelectronic devices. While prior research has extensively investigated heat sink design, this work offers novelty by employing ANSYS Icepak software for simulations. This approach enables a comprehensive thermal performance and pressure drop analysis for two distinct fin cross-sections. The study investigates heat sink assemblies housed within a confined space, simulating a realistic operating environment for microelectronic devices. The heat sink is designed to cool a single heat source (chip) mounted on a substrate board. In this paper, two types of fin sections, circular and conical, are studied for two types of fin configurations, inline (IA) and staggered (SA), which are analysed with 36 fins in each case. Each fin is constructed from aluminium and has specified dimensions. Air serves as the cooling fluid within the cabinet, dissipating heat generated by the chip. When comparing the performance of circular pin and cone fins at the same power and mass flow rate, the results indicated that the maximum temperature for circular pin fins is 0.46% of the maximum temperature for cone fins, and they have a higher pressure drop, especially for staggered arrangements. Moreover, the maximum temperature for staggered arrangements is lower than that for inline configurations by a factor of up to 1.17% and 2.035% for circular fins and cone pin fins, respectively. This article focuses on a deep understanding of the design of microelectronic cooling systems. It aims to continuously improve pressure and thermal efficiency by maintaining the minimum limits of pressure drop within the confined space and obtaining the optimal configuration for efficient heat dissipation.

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.

Numerical investigation on the thermal performance of perforated and non-perforated twisted fins at different twisting angles

The present study numerically investigated the effect of variations in the twisting angle and perimeter of diamond-shaped perforation on the heat transfer of twisted fin heat sinks. The study showed a possible configuration of a heat sink design, aiming to improve heat transfer and the hydrothermal performance factor (HTPF). ANSYS/FLUENT computational fluid dynamics software was used to perform the simulations, and the Reynolds-averaged Navier–Stokes-based k−ε turbulence model was used. Results revealed that a maximum of 46 % enhancement in the Nusselt number and a 25 % increase in (HTPF) could be attained with a twisting angle of 540° in comparison with conventional cylindrical fins. Furthermore, the variation in perforation perimeter at a twisting angle of 540° resulted in a maximum of 28 % enhancement in the Nusselt value and a 36 % enhancement in HTPF in comparison with the twisted fins with no perforations. Therefore, this configuration is recommended as the optimal heat sink configuration.

Simulation on the effect of filling porous medium on the performance of thermally conductive plastic heat sinks

High thermally conductive plastics have the characteristics of corrosion resistance, easy processing, and high thermal conductivity and can be used in corrosive environments or complex-shaped heat sinks. However, its thermal conductivity is still significantly lower than that of traditional metal heat sinks. Therefore, it is necessary to optimize the heat dissipation performance design. Based on the N–S equation and the k-ε turbulence model, the effect of porous media filled in the thermally conductive plastic heat sinks on its heat dissipation performance is studied. We compared this optimizing method with adding vortex generators in the literature. The maximum temperature of the heat sink bottom decreases by 9.3 °C. The pressure drop reduces by 55 %, and the Nusselt number increases by 9.3 %. The optimized heat sink has a hydrothermal performance factor (HTPF) 1.41. The heat dissipation performance can be similar to that of an aluminum heat sink. This study provides optimization ideas for expanding the application of thermally conductive plastics in heat sinks.

Optimization of Microchannel Heat Sink for Thermal Performance and Pressure Drop using Central Composite Design of Experiment

Optimization of Microchannel Heat Sink for Thermal Performance and Pressure Drop using Central Composite Design of Experiment

Investigation on the thermal and hydraulic characteristics of the micro heat sinks with grooves and pin fins by Taguchi-based sensitivity analysis

The heat dissipation issue of the micro electronic devices seriously restricts their application in the aerospace, national defense, communication, etc. The novel heat sinks with trapezoidal grooves and rectangular pin fins are proposed to meet the cooling requirement of the high-power devices. The cooling effect, thermohydraulic characteristics, total efficiency and thermodynamic performance of the heat sinks are studied by three-dimensional numerical simulation. Firstly, the influence of the relative position between the grooves and the pin fins on the thermohydraulic performance is explored in detail. Secondly, Taguchi optimization and analysis of variance are adopted to quantitatively analyze the impact degree of the pin fin width, length and height on the Nusselt number, friction factor and total performance index. The optimal structures are obtained for different objectives. Lastly, the temperature performance, total performance and the irreversibility of the optimal structures are compared thoroughly. New findings include that: the best arrangement of the grooves and pin fins is obtained, which enhances the Nusselt number by 1.5 times compared to the smooth heat sink. The fin width is the most critical factor for the heat transfer and flow, while the fin length shows the greatest importance in the overall performance. The optimized heat sink with the fin width of 50 μm, length of 60 μm and height of 150 μm reduces the peak temperature by 12.3 ℃ compared to the smooth heat sink for Reynolds number of 303. This heat sink yields the highest total performance index with 1.43 for Reynolds number of 368 and significantly reduces the irreversible loss. Moreover, the optimized heat sink with the fin width of 10 μm, length of 60 μm and height of 100 μm reduces the friction factor by 61.39 % compared to the original structure for Reynolds number of 635, which is beneficial to reduce the energy consumption. The quantitative analysis of the parameter sensitivity for novel heat sinks reveals the mechanism of the heat transfer enhancement by modifying the geometric parameters and provides an effective solution for thermal management of the high-power devices.

An approach for topology optimization of heat sinks for two-phase flow boiling: Part 2 – Model calibration and experimental validation

Flow boiling offers increased heat transfer coefficients and effective heat capacity rates that can be leveraged by topology optimization (TO) to generate high-performance microchannel heat sinks. Topology optimization of heat sinks having two-phase flows can be accomplished using the homogenization approach wherein designs are represented as spatially varying distributions of microstructures, as demonstrated in Part 1 of this two-part study. Flow and heat transfer within the microstructures are captured using a two-phase mixture model featuring an effective porous medium formulation. However, closure of these governing equations requires empirical correlations for pressure drop and heat transfer that are specific to the operating conditions, geometry, and surface finish. Therefore, it must be demonstrated these available correlations can be successfully calibrated over a range of microstructural variations present within the homogenization framework, so as to attain the required prediction generality and accuracy needed to ensure the resulting designs achieve Pareto-optimality. This Part 2 of our study successfully demonstrates a comprehensive end-to-end process for two-phase flow model calibration, topology optimized design generation, and experimental validation of optimized performance for flow boiling heat sinks. To this end, a TO algorithm with the homogenization approach and a two-phase mixture model is implemented using available flow boiling correlations for microchannels. A set of uniform pin fin calibration samples are additively manufactured and experimentally tested under flow boiling at various flow rates and heat inputs for model calibration. All of the unknown/free coefficients in the adopted correlations are determined by minimizing the error between the model predictions and the experimental measurements using gradient-based optimization. The calibrated topology optimization algorithm is then used to generate a Pareto-optimal set of heat sinks optimized for minimum pressure drop and thermal resistance during flow boiling. Experimental characterization of these additively manufactured heat sinks, unseen during the model coefficient calibration process, reveals that the measured Pareto optimality curve matches that predicted by the topology optimization algorithm. Lastly, a heat sink design is generated for a design space involving multiple hot spots and background heating to showcase the capability of the experimentally calibrated two-phase topology optimization algorithm at handling complex boundary conditions. The optimized heat sink intelligently distributes an adequate amount of coolant flow to each of the heated regions to avoid local dry-out. This work demonstrates a complete framework for two-phase topology optimization of heat sinks through experimental calibration of flow boiling correlations to the porous medium used by the homogenization approach.

Optimum geometry of some heat exchangers

Heat exchangers are present in our daily living and industrial applications. The size scale of heat exchangers is very large ranging from very small chips in electronics to huge equipment in process and energy industry. In the paper optimization approaches of some industrial examples are given. The goal is to present how analytical results can and must be used in multi-objective optimization of applications. The details of equations are not given due to page limits but they are found in the literature. The main goal is to show how numerical, analytical and optimization methods can be and must be combined in optimization of exchanger design and performance. The performance depends on very many factors and contradictory requirements must take into account such as maximization of heat transfer and simultaneously minimize for example the weight and size. Modifications of four existing applications are component placement on a wiring board, optimization of heat sink in power electronics, quality control in a glass tempering and optimization of a very huge heat exchanger called economizer in a recovery boiler.

CFD simulation and geometric optimization of a novel baffle heat sink for power electronics cooling

The electric drivetrain of an electric vehicle typically has two fluid circuits: an oil circuit for lubrication and a water-glycol circuit for cooling. Eliminating the water-glycol circuit can result in a more compact and lighter drivetrain. However, this requires the drivetrain components to be cooled with oil as coolant, which has inferior heat transfer properties compared to water-glycol mixtures. This is particularly challenging for the power modules in the power electronics unit, which exhibit some of the highest heat fluxes in the drivetrain. This study focusses on the design and optimization of a novel type of heat sink for laminar flows with baffles to guide the flow in four different directions. This has two main advantages: the baffles act as fins and increase the heat transfer area and they introduce a swirling motion in the oil thereby disturbing the boundary layers continuously. Computational fluid dynamics simulations using Ansys Fluent are performed to evaluate the thermohydraulic performance of the heat sink. The influence of design parameters such as the height and thickness of both fins and baffles and the baffle spacing in horizontal, upward and downward direction was evaluated by simulations with several combinations of the design space, considering manufacturing constraints. The optimization of the design showed that the fin thickness, horizontal baffle spacing and baffle length should be as small as possible, while there were optimal values for fin height, upward and downward baffle spacing, streamwise baffle spacing and baffle thickness. The simulations show that the thermal resistance of the baffle heat sink can be 19% lower than that of a benchmark pin fin heat sink at equal pumping power.

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.

Comprehensive examination of topologically optimized thermo-fluid heat sinks

This study investigates the thermal performance of topologically optimized heat sinks. The primary aims are to conduct a comprehensive parametric study, compare thermal outputs with the benchmark model, and validate numerical simulations through experimental testing. Multi-objective topology optimization is formulated based on thermal compliance and power dissipation. Selected optimized models were built and tested. The parametric study revealed promising design variables, leading to numerical convergence with interconnected flow paths. The promising variables were found under weighted thermal compliances (wh) between 0.3 and 0.9 and targeted liquid fractions (θFV) between 0.5 and 0.8. Additionally, at low operating pressures, for example, at 0.01 kPa, the temperature difference between optimized and benchmark models could be as much as 30 °C. Nonetheless, the temperature difference between both models became smaller at higher operating pressures. Furthermore, the comparison of temperature measurements, pressure drops, and thermal imaging showed reasonable agreement between experimental and numerical results. Additionally, the effect of design variables on thermal performance was confirmed through experiments. The heat sink with higher wh exhibited a lower temperature than that of the model with lower wh. In summary, this research highlights the crucial role of design variables in achieving a balance between temperature and pressure drop.

Swarm-based multi-objective optimization of double-layered microchannel heat sink with hybrid solid-porous ribs

The current article focuses on the thermal and hydraulic optimization of a double-layered microchannel with hybrid solid-porous ribs. Therefore, for both upper and lower layers, solid-porous ribs, having different thickness ratios of porous and solid, are considered. The ratio of solid-porous thickness in the upper and lower layers and Reynolds number variations are taken into account as design variables. The present study is conducted to find an optimum design by which not only thermal performance improves, but also power consumption reduces. At the initial step, the double-layer microchannel is simulated using artificial neural network. The second step involves the application of the optimum network and the microchannel inputs for minimizing the thermal resistance and the power consumption single-objective and multi-objective type’s optimization problems are solved. The two mentioned optimization problems in the proposed strategy are targeted using four swarm-based algorithms. Results indicated that the designed neural network has a maximum error of 4% for producing the desired outputs. Moreover, the single-objective optimization of the second stage showed that by the porous ratios of 0.19 and 1 for the upper and lower layers, respectively, and Reynolds number of 578.7, the minimum values of pressure drop and overall thermal resistance are achieved.

Thermo-hydraulic characteristics and structural optimization of supercritical CO2-cooled microchannel heat sink

Supercritical carbon dioxide (sCO2) serves as an efficient working fluid in microchannel heat sinks (MCHS), effectively mitigating heat dissipation challenges in high heat flux microelectronic devices. Nonetheless, the issue of flow acceleration affecting micro-scale heat transfer, especially in channels with diameters <0.2 mm, warrants additional investigation. Flow acceleration exacerbates temperature non-uniformity, consequently diminishing heat transfer efficiency. Numerical simulations were conducted to examine the thermo-hydraulic characteristics of sCO2 in microchannels featuring complex structures including ribs and cavities. The channel had a diameter of 0.133 mm, with heat flux to mass flow rate (q/G) ranging from 0.1 to 0.5 kJ/kg. Three-dimensional entropy production rate (Sg) maps and corresponding heat maps were utilized to establish boundary conditions and evaluate heat transfer optimization. Additionally, structural optimizations were performed to rectify temperature non-uniformity in sCO2 within MCHS. The results indicate that the entropy production rate (Sg) of sCO2 initially decreased and then increased with the increase in q/G and dimensionless enthalpy (h*). The optimized MCHS demonstrated enhanced temperature uniformity, with a maximum temperature difference of 1.8 K, notably lower than that of the non-optimized MCHS (5.3 K). This study offers a theoretical basis for the design and implementation of sCO2 in micro-scale MCHS.

Liquid-cooled heat sink design methodology with technical and commercial viability considerations: Case study of a partially 3-D printed prototype

A two-step methodology is proposed for the design and optimization of liquid-cooled heat sinks, where manufacturing costs are included as a commercial viability assessment metric. First, manifold modifications were made to reduce pressure losses in the baseline design. Second, a full-factorial parametric computational fluid dynamics (CFD) study fed an artificial neural network (ANN) model for further optimization. The aforementioned methodology was applied to the optimization of liquid-cooled heat sinks for CPU cooling. The baseline design consisted of a 3-D printed resin plenum mounted on a metallic heat spreader with parallel fin channels. The plenum delivers a slot jet along the center of the heat sink into a central passage that bifurcates the fin channels. An improved plenum design with ∼11% lower pressure losses than the baseline model was generated after the first optimization step. The designs generated in the parametric CFD study achieved average thermal resistances as low as 0.01 K/W for a theoretical pumping power range of 50–350 mW. A representative design from this study was manufactured and experimentally tested to assess the simulation approach, providing reasonable agreement with the numerical results. Consecutively, the ANN allowed for a higher resolution sampling of the design space, where optimal configurations were found in terms of an overall thermo-hydraulic performance parameter and an additional metric accounting for manufacturing costs. The methodology reported herein caters to heat sink designers seeking commercialization of their prototypes as the contrast between technical performance and manufacturing costs is addressed. Additionally, the mathematical tools utilized allow for cost-effective topology optimizations.

Design and Optimization of Heatsink for an Active CPU Cooler using Numerical Simulations

Heat generation in CPUs with high computing performance has been a very serious issue that deteriorates their performance. To ensure that CPUs operate at their maximum potential, it is essential to maintain their temperature below 80 °C. Forced convection coolers comprising of a heatsink and fan are considered the most effective means of satisfying operating temperature requirements for a CPU in order to ensure its maximum performance. A heatsink design paired with a fan with airflow speed of 80 cubic feet per minute (CFM) for a CPU Cooler targeted at CPUs with maximum heat generation of 380 watts operating in ambient temperature of 25 °C, is developed using numerical methods of Computational Fluid Dynamics (CFD) and topology optimization using ANSYS Mechanical and ANSYS Fluent. Various fin profiles, fin arrangements, fin numbers and heatsink materials are comparatively analyzed. The best results from the comparative analyses are combined to present a base design capable of keeping the CPU temperature below 80 °C, which is the requirement for ensuring maximum computing performance. A 30 fin heatsink with covered rectangular plate fins in an arc-shaped placement configuration is determined to provide the maximum cooling performance. In materials, Silicon Carbide resulted in the lowest CPU temperature of 78°C, followed by copper at 84 °C. Silicon Carbide heatsink successfully managed to satisfy the requirements for maximum CPU performance. Copper heatsink is unlikely to cause CPU failure, but it fails to meet conditions for maximum CPU performance. In addition, this base design is then optimized for material cost reduction using topology optimization which resulted in 13% reduction in material cost with a negligible cooling performance reduction of only 0.32%. The overall design of the cooler can be improved by incorporating fan design and various CPU load conditions into the design parameters in future research.