Heat Sink Design Research Articles

Thermal Characterization Methodologies for Experimental Minichannel Heat Sink Designs in Printed Circuit Board Assemblies

There has been a growing demand for novel, highly efficient, power-saving cooling solutions in recent years. In many cases, standard cooling techniques offer only limited opportunities to prevent the overheating of circuits. Such issues concern high-speed Printed Circuit Board Assemblies (PCBA) in data centers and telecommunication racks, where the flow of the cooling medium is obstructed due to the lack of space. Size limitations can also be a serious problem when cooling high-power devices because the devices consume a large space. Since the heat sink-based cooling solutions and the sophisticated IC packages only deal with one possible heat flow path, we were given the idea of enhancing the secondary heat flow path towards the Printed Circuit Board (PCB). Led by this intention, the idea of creating an embedded minichannel system inside the circuit board and circulating the cooling agent was realized. Through this method, we could decrease the board-to-ambient thermal resistance significantly. This paper presents the demonstration and feasibility study of this method. One of the main aims of this study is to demonstrate the applicability of the proposed concept in PCBAs, where the primary concerns are the low-cost manufacturability and available space. The other goal is to create an adaptation of the standard thermal characterization methodologies to deal with the specific dissipating components in the PCBA demonstrators. In the first part, the manufacturing technology is elaborated on, and its efficiency is characterized by thermal transient testing and Computational Fluid Dynamics (CFD) simulations. For these use cases, it was noted that the cumulative thermal resistance decreased by approximately 60% when a volumetric flow rate of 100 ccm was applied in the minichannels. In the second part, a more sophisticated technology demonstration is realized and characterized by adding the proposed embedded minichannel heat sink to an existing high-speed PCBA. A specific thermal transient testing was implemented specifically for this use case, and it was carried out on programmable logic devices by utilizing general-purpose programmable logic to construct the necessary measurement methods. In the future, this feature can be used in different logic circuit designs where it is not possible to determine the junction temperature directly.

Innovative heat sink design for enhanced cooling efficiency in Dual Active Bridge (DAB) topology

Abstract After in-depth research and analysis, aiming at the heat generation mechanism and limitations of the current heat dissipation method, this paper proposes an innovative heat dissipation design scheme. By optimizing the structural design of the heat sink, the heat dissipation surface area is increased, thus achieving more efficient heat emission and maintaining the optimal operating temperature of the equipment. Experimental data show that this new heat dissipation design significantly improves the cooling efficiency, an increase of about 60%, and provides support for the performance improvement of high-power power products, which brings a reliable and efficient cooling solution for related industries.

Fabrication of microchannel heat sink using additive manufacturing technology: A review

Additive manufacturing is a cutting-edge process that enables the creation and development of complex shapes, opening new avenues for advanced heat sink designs that maximize heat transfer while minimizing pressure drop. This review provides an overview of recent results and insights from global researchers on the additive manufacturing of microchannel heat sinks. It discusses various novel microchannel heat sink types fabricated using additive manufacturing and the complexities involved in their fabrication. Additionally, the review explores geometric configurations, the application of computational optimization methods, and the impact of surface roughness on heat transfer and pressure drop. The primary focus is on the fundamental advantages of additive manufacturing in addressing complex heat transfer designs. However, the review also highlights limitations restricting its benefits in specific applications, such as material handling and availability. This review identifies future challenges for creating novel heat sinks with complex geometries and opportunities for advancements in heat transfer technology.

Numerical analysis of magnetohydrodynamic effects on hybrid nanofluid cooling in high-density servers

This study numerically examines active CPU cooling using hybrid nanofluids in a novel heatsink design. The proposed heatsink is a parallelepiped block filled with Al2O3-CuO/water nanofluid, traversed by four strategically placed cooling tubes. It meticulously investigates the effects of CPU temperature (10³ ≤ Ra ≤ 10⁶) and magnetic field strength (0 ≤ Ha ≤ 100) on overall cooling capacity. With hybrid nanofluids, heat transfer and cooling efficiency are substantially improved, according to comprehensive finite element analysis conducted in COMSOL Multiphysics. The study provides valuable insights for designing high-performance CPU cooling systems, carefully considering nanofluid properties, diverse thermal conditions, and complex magnetic effects. The promising results show that using advanced hybrid nanofluids and an optimized magnetic field can significantly enhance the cooling performance of modern high-powered CPUs. The groundbreaking research highlights the immense potential of combining cutting-edge nanotechnology and magnetohydrodynamics in innovative thermal management solutions. This novel approach could lead to more efficient, compact, and adaptable cooling systems for next-generation electronic devices, effectively addressing the persistent challenge of heat dissipation in high-performance computing environments.

Device packaging and integration optimization based on neural network method: Effect of microchannel structure on heat sink performance

With the continuous improvement of power density of electronic device packaging, microchannel structure based on advanced packaging integration technology has become one of the hot topics in thermal management research. In this paper, two heat sink models are numerically simulated: rectangular microchannel and microchannel-pinfin hybrid. The effects of microchannel structure, inlet/outlet arrangement and pinfin design on heat sink performance were studied. The heat sink performance is evaluated by the maximum temperature at hotspot area, the total thermal resistance and the mean absolute temperature deviation (MATD). The research results show that at the same Reynolds number, the hybrid structure with pinfin has better heat sink performance. Compared with the rectangular microchannel structure, the maximum temperature at the hotspot area is reduced by 20.45 K and the total thermal resistance is reduced by 5.9 %. Compared with the three inlet/outlet arrangements of I-type, U-type and Z-type, the I-type hybrid structure has the best heat sink performance. The average absolute temperature deviation is about 10 K at high Reynolds number, and the temperature distribution is more uniform. In addition, the heat sink performance is improved by increasing the pinfin size to expand the heat transfer area. This paper uses simulation results to build an artificial neural network model in order to quickly and accurately predict numerical results under different parameter conditions. The network model has good accuracy and robustness, with a mean absolute error of 0.376 %. The prediction model takes heat source power, Reynolds number and pinfin structural parameters as input. Rapidly predicting the performance of heat sinks with different structural parameters under different boundary conditions will effectively save experimental and computational costs. This research provides new ideas and tools for optimizing heat sink design, and helps improve the application of microchannel cooling technology in electronic devices.

Heat sink design and topology optimization of a DC/AC converter for a general aviation hybrid-electric aircraft

This work aims to explore the potential of topology optimization in the design of forced air-cooled heat sinks for inverters equipping hybrid-electric aeronautical propulsion systems. Compared to the automotive applications that are driving the electrification of the transportation sector, the design of heat sinks in aircraft requires minimizing not only the thermal resistance and pumping power of the fans, but also the weight and volume. The challenge is further made more difficult by ambient air temperature and density that vary with the aircraft’s altitude. Considering the inverter of a real aircraft equipped with a hybrid electric propulsion system, the authors first designed conventional heat sinks with finned configurations by applying semi-empirical formulations and then a free-form heat sink by exploiting topology optimization. Conventional heat sinks serve as a reference for carrying out the evaluation with heat sinks based on topology optimization. The latter prove to be characterized by superior performance as the thermal resistance is up to 7 % lower, the pumping power of the fan is reduced by 34 % at the same inlet velocity and the weight saving is around 45 %. Finally, the heat sinks were verified at the system level by having their models integrated into a completed aircraft model.

Influence of pin fins and channel geometry on the hydrothermal performance of hexagonal mini-channel heat sink for cooling cylindrical batteries

This study numerically and experimentally examined the effects of pin fin configuration and channel geometry on the performance of a hexagonal mini-channel heat sink (HMCHS) to cool cylindrical lithium-ion battery cells. Various configurations of HMCHS with circular pin fins are studied, including circular fins centrally positioned within flat channels, circular fins positioned within grooved channels, circular fins situated within hybrid channels transitioning between wavy and straight channels and circular fins placed within hybrid channels that incorporate secondary flow channels between the primary flow channels. This numerical study utilized the finite volume method to investigate the laminar water flow at Reynolds numbers below 800. Findings showed that the HMCHS exhibited superior thermal performance compared with the conventional cylindrical mini-channel heat sink design. Moreover, the incorporation of pin fins into the HMCHS design was more effective in enhancing the Nusselt number than simply increasing the Reynolds number across various configurations. Meanwhile, the hybrid channel design with secondary channels, combined with the addition of pin fins, achieved the optimal overall performance of the HMCHS, resulting in the highest performance index of 1.88.

Performance evaluation and experimental verification of optimizing fin angles in adjustable- configuration heat sinks

Current heat sink designs typically assume uniform heat flux densities. However, applications such as integrated circuit chips and aircraft power modules often face nonuniform or even time-varying heat fluxes. Under these conditions, conventional fixed-configuration heat sinks are inadequate, and corresponding research is insufficient. This paper presents an adjustable-configuration heat sink with a rotatable fin and explores its flow and heat transfer characteristics under water cooling via simulations and experiments. Genetic algorithms optimize the fin angles for various heat flux densities to reduce the substrate temperatures, and compute numerical control (CNC) technology is used to fabricate and adjust the experimental components for optimal performance under different conditions. The proposed adjustable-configuration heat sink exhibited superior temperature uniformity and cooling performance under various heat flux density conditions. Under uniform heating, peak substrate temperatures are reduced by 15.68 and 14.01 K for the I-type and Z-type adjustable configuration heat sinks, respectively, compared to conventional multi-channel heat sink. For non-uniform heating, the optimized configurations lowered the temperatures in the high-heat regions by 2.8 to 5.1 K. This design, which incorporates an adjustable heat sink configuration, effectively adapts to varying heat flux density scenarios, making it a strong candidate for advanced thermal management applications.

Thermal performance optimization for a tapered heat sink of bus bar conductor using definitive screening design

This study examines and optimizes four design parameters of a bus duct conductor's heat sink: fin pitch, fin height, fin thickness, and the number of fin valleys. Average surface temperature and Nusselt number are chosen as the thermal performance criterion of the heat sink. A Definitive Screening Design is employed as a statistical method to reduce the number of optimization runs required while minimizing the aliasing. The regression analysis, analysis of variance, main effect analysis and optimization are conducted to optimize the heat sink design parameter and its thermal performance. The current results provide an ideal heat sink design for the casing of bus duct conductors. A fin pitch of 4 mm, fin height of 6.5 mm, fin thickness of 1 mm, and six fin valleys are determined to be the most optimal combination of design parameters. The optimized responses' average surface temperature and Nusselt numbers are 72.05 °C and 21.59, respectively, with 2.97 % and 6.25 % deviation from the predicted values of the empirical equation. The experimental results are benchmarked against the IEC 60439-1 and IEC 60439-2 standards. The current analysis is expected to provide more insight into the impact of design factors on the thermal performance of a bus duct conductor.

Twice-topology optimized heat sinks for enhanced heat transfer performance: Numerical and experimental investigation

Since the heat dissipation problem is always confusing and hindering the computing power improvement of electronic chip, an effective thermal management strategy is critical to relieve these problems. In this work, a new twice topology optimization design method combining topology optimization and image processing to design heat sinks is presented, which extends topology optimization from 2Dimention (2D) to 3Dimention(3D). Firstly, on the horizontal design domain, the conventional topology optimization is conducted for the minimization of average temperature/standard deviation. Then the optimal shape of liquid domain is converted into 1D flow routine by thinning algorithm. After that, another topology optimization is performed on the flow channel cross-section plane to get the best cross-section shape of channels. The liquid domain of the final heat sink is then obtained by scanning the optimized flow channel cross-section along the 1 Dimension (1D) flow routine and solving the interference by introducing cylinder joints. Finally, two kinds of twice topology optimized heat sinks including TTOHS-1 with minimized temperature variation as optimal goal and TTOHS-2 with minimized average temperature as optimal goal are generated by combining the liquid domain and a cuboid using Boolean Operation. The performance of heat sinks is numerically investigated, and the results indicate that the thermal performance of TTOHS-1 and TTOHS-2 are much better than that of the traditional heat sink with straight channels (TSCHS). When Re = 689, the average temperature and the maximum temperature of the heat source surface of TTOHS-1 are decreased by 4.99 % and 6.29 % respectively, compared to the TSCHS. The Nusselt number is increased by 46.16 % while the thermal resistance is reduced by 33.13 %. At last, the thermal and flow performance of the TTOHS-1 is studied by conducting experiments, showing that the numerical results agree well with that of the experiment.

Systematic design of tree-like branching network microchannel heat sinks for enhanced heat transfer with nanofluids

Branched or tree-shaped networks of microchannels are often preferred heatsink designs for microelectronic cooling due to their ability to offer a substantially large surface area-to-volume ratio. Designing an optimized tree-shaped heatsink in terms of hydrothermal performance poses challenges due to the intricate geometry and small-scale fluid–structure interactions involved, making prototyping challenging. We propose a systematically designed microchannel network heat exchanger inspired by tree branching patterns, aiming for ease in rapid prototyping and improved flow distributions offering enhanced thermal performance. Starting from a simpler geometrical consideration, we systematically improve the design by introducing a pin fin at the junction for improved flow distribution and then by imparting a converging angle in the channel for enhanced thermal performance. Additionally, we conduct an entropy generation analysis to examine the thermal performance of various nanofluid concentrations within the proposed device and witness significant thermal performance improvement that can benefit the thermal management of microelectronic components and other cooling applications.

Constructal design of a hybrid heat sink with rectangular microchannel and porous fin in a 3D electronic device with artificial neural-network, NSGA-II and different decision-making methods

Constructal theory is used to build a hybrid heat-sink model with rectangular microchannel and porous fin in a 3D electronic device. Firstly, constructal design is conducted with objective of minimizing linear weighted sum of maximum temperature-difference and pump power consumption with fixed total volumes of 3D electronic device, porous fin and microchannel. The optimal microchannel aspect ratio and elemental number are gained. Secondly, multi-objective-optimization is conducted based on NSGA-II, which uses the “gamultiobj” function of Matlab's artificial neural-network toolbox. The findings indicate that when microchannel aspect ratio and elemental number are 0.29 and 38, respectively, complex function achieves its double minimum of 0.810, which is decreased by 19.0% compared to its original value. Therefore, optimizing microchannel aspect ratio and elemental number simultaneously contributes to improving the comprehensive performance of 3D electronic device. Based on LINMAP, TOPSIS and Shannon Entropy decision-making strategies, the multi-objective solution set is compared. The third decision-making method has the smallest deviation index. The corresponding optimal microchannel aspect ratio and elemental number are 0.35 and 32, respectively, which can be used as the optional structure design scheme. The research findings can serve as a new theoretical reference for designing hybrid cooling system in a 3D electronic device.

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.

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.

Theoretical investigation of height and width tapered microchannel cooling systems for ultra-high concentrator photovoltaic thermal hybrids

This paper explores the utilisation of horizontally and vertically converging microchannel heat sinks for cooling concentrator photovoltaic systems. These are compared to a straight microchannel, which is used as the control test. The primary performance parameters considered are the system's energy and exergetic efficiency and the thermal stresses generated in the solar cell. Horizontally converging channels yield more uniform temperature distributions, but the peak and average thermal stress generation increased due to the higher cell temperature. Conversely, vertically converging channels demonstrated a reduction in thermal stress generation. However, channels which converge more sharply require a substantial increase in pumping power for the same cooling-fluid flow rate which negatively impacts energy and exergetic efficiency. Notably, the control design for straight microchannels is specified to have the same manufacture difficulty across configurations, which is an often-overlooked aspect.The evaluation incorporates two irradiance profiles from concentrator optics to enhance the applicability of results. The straight microchannel structure and the vertically converging channel with a taper ratio of 0.75 are identified as the most applicable for concentrator photovoltaic application. The outcomes provide valuable insights on heat sink design and sheds light on the trade-offs between thermal performance, energy efficiency and manufacturability.

Thermal Management of Electronics under Cyclic Heat Loads Using Graphite-Assisted Heat Sink

The primary objective of this experimental study is to establish a methodology for enhancing the operational duration and concurrently reducing thermal fluctuations within cyclically functioning electronic devices. In instances where electronic devices operate with intermittent duty cycles, they are susceptible to temperature fluctuations. This, in turn, can induce thermal fatigue, ultimately posing a risk of malfunction. This study introduces a novel square-shaped heat sink design integrated with phase change material (PCM) and enhanced by vertical fins. The experimental evaluation involves subjecting this design to various heat loads characterized by sinusoidal, triangular, sawtooth, and square profiles. Initially, when different constant heat load values were employed, surprisingly, despite its lower melting point temperature, Eicosane consistently outperformed Docosane by a remarkable 37% in terms of heat sink performance in enhancing operating time. However, when cyclic heat loads with intermittently varying profiles were introduced, Docosane demonstrated superior performance. To extend the operational time and improve thermal management, expanded graphite was introduced as a thermal conductivity enhancer into PCMs at various mass fractions. Four distinct PCM mixtures were prepared, each with different expanded graphite (EG) proportions, namely: 70% PCM-30% EG, 75% PCM-25% EG, 80% PCM-20% EG, and 90% PCM-10% EG. These mixtures were rigorously tested under the cyclic heat loads defined in the study.

An Experimental and Numerical Studies of Fin-type Heat Sinks, Microchannel Heat Sink Its Cooling Performance and Design Consideration

Microchannel heat sinks (MCHS) have emerged as pivotal components in advanced thermal manage-ment systems due to their superior heat transfer capabilities. Fin-type heat sinks, essential for efficient thermal management in electronic devices, are evaluated through a series of experimental and numeri-cal studies. This paper reviews recent advancements in the design and performance analysis of various fin-type heat sinks, including micro pin-fins of different geometries and dimensions. By comparing the heat transfer efficiency and pressure drops among different designs and operating conditions, this re-view aims to provide insights into optimizing fin-type heat sinks for improved thermal management.

Experimental and numerical study on thermal management performance of PCM-based heat sinks with various configurations fabricated by additive manufacturing

Due to the low thermal conductivity of PCM, the enhancement of thermal performance becomes a crucial issue for the application of PCM-based heat sinks in electronic device cooling. To address this, efficient and integrative PCM-based heat sinks using fin and structured porous material (SPM) are designed and fabricated by additive manufacturing (AM). This work aims to investigate thermal performance of PCM-based heat sinks and the role of fin and SPM used as thermal conductivity enhancers (TCEs). The enhanced heat transfer mechanisms in PCM-based heat sinks using different types of TCEs are determined, and parametric analysis is conducted considering various volume fractions of TCEs (10 %, 15 %, and 20 %). Moreover, the effects of heating power levels and convective heat transfer coefficients on thermal behavior of PCM-based heat sink are analyzed. The results indicate that incorporating SPM in heat sink enhances thermal performance more effectively than using fins for an equivalent TCE fraction. Both heating power and convective heat transfer coefficient have a significant on thermal performance. This research demonstrates the potential of the novel heat sink with SPM in cooling electronic devices and provides the experimental and numerical database for the optimal design and future application of PCM-based heat sink.

Influence of the foam-fin structure on the thermal performance of a coupled phase change liquid cooling module

Effective thermal management is key to ensuring the reliable operation of high power electronic equipment. In this study, the strategy of phase transition and liquid cooling coupling applied to transient high power electronic equipment has been examined. In order to improve the performance of the phase changing material (PCM) in temperature control, the effects of the coupling structure have been addressed with a consideration of fin, copper foam (CF), graphite foam (GF), fin-copper foam (FCF) and fin-graphite foam (FGF) structures in heat dissipation. In this study, pure paraffin wax (PPW) was used as phase change material to prepare heat sinks based on the above five structures. The experimental study investigates the impact of different thermal conductivity strategies on temperature control characteristics, with a focus on cold capacity recovery and the combined phase change and liquid cooling, using pure paraffin wax module as a reference. The results have revealed that the fin-foam coupling structure delivers a better PCM performance than the single fin or foam structure. Operating at a heating power of 10 W, 15 W and 20 W, the temperature control time of the FGF structure was increased by 13.6 %∼14.6 % relative to the GF structure. At 15 °C with flow rates of 1 L/min, 1.5 L/min, 2 L/min liquid cooling conditions, the cooling capacity recovery time was reduced by 18.8 %, 17.2 %, 19.7 %, respectively. In the phase-change liquid-cooling coupling temperature control experiment, the final temperature increase in the FGF system was 11.7 °C -15.2 °C lower than that of the GF system under the same water temperature and volume flow for a 50 W heat source. The incorporation of fins also enhanced the thermal conductivity strengthening capability of the copper foam and reduced the cold recovery time. Based on the comprehensive evaluation, the FGF structure demonstrates superior temperature control performance and cold recovery characteristics of PCM, making it an optimal strengthening method. Following closely are the FCF, GF, Fin and CF structures. Compared to pure paraffin modules, these five modules exhibit varying degrees of improvement in temperature control and cold capacity recovery efficiency. This study provides guidance for optimizing heat sink design based on PCM in electronic applications.

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.