Heat Sink Technology Research Articles

Microchannel Heat Sinks—A Comprehensive Review

An efficient cooling system is necessary for the reliability and safety of modern microchips for a longer life. As microchips become smaller and more powerful, the heat flux generated by these chips per unit area also rises sharply. Traditional cooling techniques are inadequate to meet the recent cooling requirements of microchips. To meet the current cooling demand of microelectromechanical systems (MEMS) devices and microchips, microchannel heat sink (MCHS) technology is the latest invention, one that can dissipate a significant amount of heat because of its high surface area to volume ratio. This study provides a concise summary of the design, material selection, and performance parameters of the MCHSs that have been developed over the last few decades. The limitations and challenges associated with the different techniques employed by researchers over time to enhance the thermal efficiency of microchannel heat sinks are discussed. The effects on the thermal enhancement factor, Nusselt number, and pressure drop at different Reynold numbers in passive techniques (flow obstruction) i.e., ribs, grooves, dimples, and cavities change in the curvature of MCHSs, are discussed. This study also discusses the increase in heat transfer using nanofluids and how a change in coolant type also significantly affects the thermal performance of MCHSs by obstructing flow. This study provides trends and useful guidelines for researchers to design more effective MCHSs to keep up with the cooling demands of power electronics.

Optimizing Thermal Management: An Evaluation of Embedded Aluminum-Ammonia Heat Pipes Honeycomb Sandwich Panel as a Heat Sink for Satellite Use

This study presents an innovative approach to enhancing thermal management in satellite applications by utilizing an embedded aluminum-ammonia heat pipes honeycomb sandwich panel (HPA-PNL) as a high-performance heat sink. The study focuses on developing and evaluating this advanced heat sink technology, addressing the challenges associated with assessing its performance and suitability for satellite use. The research explores the selection of materials and testing methodologies, highlighting the significance of overcoming existing limitations in the absence of standardized testing methods. The results of the thermal conductivity in Z-directions (KZ) indicated that the areas on top of the heat pipes show higher thermal conductivity than those on top of the honeycomb core. Also, the effect of background heat sources and different kinds of thermal interface material (TIM) on HPA-PNL performance is insignificant. The heat dissipation through the heat pipe is substantial, emphasizing the effective ability to dissipate heat for an HPA-PNL with many heat sources acting simultaneously. The outcomes of this study reveal promising testing methods for evaluating the KZ of the HPA-PNL, proposing the potential of the embedded aluminum-ammonia heat pipes honeycomb sandwich panel as a highly effective and efficient heat sink for satellite systems, thus contributing to the advancement of satellite technology.

Performance analysis and structure optimization for concentrated photovoltaic-phase change material-thermoelectric system in space conditions

High-efficient thermal management is urgently needed for concentrated photovoltaic-thermoelectric hybrid system due to the high heat flux. In present paper, a three-dimensional model for the hybrid system in outer space conditions was established by coupling phase change temperature control and radiation heat sink technologies to find the propriate thermal management scheme. Firstly, the three shortcomings in the typical hybrid system were proposed and their adverse effects on efficiency were elucidated. Then, a heat transfer pillar for temperature control unit and a newly designed circular fins for heat sink were designed. The effects of structure parameters on power generation performance were investigated, and the interaction between temperature control unit and heat sink were discussed. The results show that the hybrid systems with the newly designed heat transfer pillar and circular fins have higher efficiency. After that, a united structure optimization by artificial neural network-multi-objective genetic algorithm was performed to solve the interaction and to balance the electrical efficiency and power density of hybrid system. The comprehensive power generation performance of hybrid system can be further improved after the optimization. The system with PCM thickness dPCM = 6.33 mm, heat transfer pillar width a = 18.19 mm, fin length L = 49.99 mm and fin radius R = 50 mm, has the maximum average total efficiency (31.83%, 2.98% higher than the typical system); the system with dPCM = 3.02 mm, a = 10.05 mm, L = 47.03 mm and R = 25.86 mm, has the maximum average power density (36.97 W/kg, 15.78% higher than the typical system).

Mono and hybrid nanofluid based heat sink technologies - A review

This paper presents a review of mono and hybrid nanofluid using heat sink technologies, which is the foremost task of new generation technology in cooling electronic devices. Heat generation in a tiny electronic device is the main factor to be prevented to enhance the heat transfer. One prominent remedy for this problem is to adopt mono and hybrid nanofluid based microchannel heat sinks are considered to be the recent trends.In this article, a state-of-the-art review of heat sinks, nanofluids preparation and characterization techniques have been carried out. The study begins with an overview of the heat sink, designing parameters, research work carried out in the last decade using mono nanofluids and hybrid nanofluids followed by the analysis of the research work carried out in the last decade in terms of different geometries of MCHS to examine the diverse factors like pressure drop, heat transfer coefficient, and critical heat flux. Current challenges and opportunities for future research are presented as well.

Thermal management of microwave electronics in the radar system

This work aims at improving the state of the art cooling technique for Transmit Receiver Modules (TRMs) by employing the micro channel heat sink technology. The key objectives of this study are to (1) optimize process parameters (Channel width, Channel Height, and Fin width) of heat sink for minimal thermal resistance, (2) conduct numerical simulation of heat sink with optimized parameters, and (3) design and fabricate micro channel heat sink to cool TRMs with heat flux of 100 W/cm2. Taguchi L9 orthogonal array is formulated to optimize the parameters. CFD simulation method is employed to obtain the optimum combination of factors. The optimum combination of factors (Channel height-4 mm, Channel width-0.3 mm and Fin width-0.3 mm) for minimum thermal resistance is found. A heat sink is fabricated with the optimized parameters. Through experimental investigation, the thermal resistance of the fabricated heat sink is determined as 0.0636 °C/W which is found to be capable of cooling TRMs with 100 W/cm2.

열전도성 입자를 활용한 시트용 점착제의 점착 특성과 방열특성 연구

Improvement of heat sink technology related to the continuous implementation performance and extension of device-life in circumstance of easy heating and more compact space has been becoming more important issue as multi-functional integration and miniaturization trend of electronic gadgets and products has been generalized. In this study, it purposed to minimize of decline of the heat diffusivity by gluing polymer through compounding of inorganic particles which have thermal conductive properties. We used NH-9300 as base resin and used inorganic fillers such as silicon carbide(SiC), aluminum nitride(AlN), and boron nitride(BN) to improve heat diffusivity. After making film which was made from 100 part of acrylic resin mixed hardener(1.0 part more or less) with inorganic particles. The film was matured at for 24h. Diffusivity were tested according to sorts of particles and density of particles as well as size and structure of particle to improve the effect of heat sink in view of morphology assessing diffusivity by LFA(Netzsch/LFA 447 Nano Flash) and adhesion strength by UTM(Universal Testing Machine). The correlation between diffusivity of pure inorganic particles and composite as well as the relation between density and morphology of inorganic particles has been studied. The study related morphology showed that globular type had superior diffusivity at low density of 25% but on the contarary globular type was inferior to non-globular type at high density of 80%.

Numerical study on layout of micro-channel heat sink for thermal management of electronic devices

Aiming at improving the structures of micro-channel heat sinks for chip cooling techniques, four types of heat sinks, including traditional micro-channel (TMC) heat sink, rectangle column fin heat sink, single-hole jet-cooling heat sink and double-layer micro-channel heat sink were modelled. And the characteristics of flow and heat transfer in these heat sinks were investigated by numerical method. The numerical results show that the layout of microchannel heat sink is very important to the fluid flow and heat transfer. It is positive for improving thermal performance to fill metal foam in the inlet header by strengthening flow distribution uniformity. In comparison to traditional microchannel rows, the pin-fin array way of microchannel arrangement will strengthen the thermal performance of the overall heat sink due to the better field coordination characteristic. Although the jetting cooling heat sink technology possesses the best chip cooling capacity, it is not proposed for the field of microchannel cooling because of a huge flowing resistant. The double-layer structure with the inlet at the bottom layer processes the second-best cooling capability at the cost of an acceptable large pressure drop. In general, under the same pumping power, there is substantial development potential on the traditional micro-channel heat sink with metal-foam inlet header and rectangle column fin micro-channel heat sink.

Compact Gravity Driven and Capillary-Sized Thermosyphon Loop for Power Electronics Cooling

A novel two-phase thermosyphon based on automotive technology is presented as a valid solution for the cooling of power-electronic semiconductor modules. A horizontal evaporator configuration is investigated. This solution is based on a 90 deg-shaped thermosyphon that allows an optimal geometrical arrangement of the cooler with limited volume occupancy, reduced air pressure drop, and weight as well as optimal thermal performance compared with standard heat-sink technology. The 90 deg-shape refers to the mutual arrangement of the evaporator body and the condenser, which are in a horizontal and vertical position, respectively. The evaporator cools three power modules with a total power loss between 500 and 1500 W. Experimental results are presented for inlet air temperatures ranging from 20 to 50 °C and for different air volume flow rates between 200 and 400 m3/h. The working fluid is refrigerant R245fa. The maximum thermal resistance (cooler base to air) attained values between 40 and 50 K/kW.

Using heat sink technology to decrease residual stress in 316L stainless steel welding joint: Finite element simulation

316L type stainless steel is widely used in chemical industries due to its excellent resistance to corrosion. But the welding residual stresses have a great effect on stress corrosion cracking. This paper used finite element method to study the effect of heat sink on residual stress. The effects of contact length and the average heat transfer coefficient on residual stress have been investigated. It is found that the heat sink technology can decrease the residual stress greatly. Compared to the model without heat sink, 20% of the peak longitudinal stress has been reduced. The heat sink decreases the dwell time during cooling from 850 °C to 400 °C, which is helpful to decrease the risk of sensitization of 316L stainless steel. With the contact length increase, the transverse stress is decreased. Further increase of the contact length has no positive effect on reducing the longitudinal stress. With the average heat transfer coefficient increase, the transverse stress is decreased greatly while the longitudinal stress decreases slightly, and some tensile residual stresses have been changed to compressive in some zone.

Feasibility study of an actively cooled tungsten divertor in Tore Supra for ITER technology testing

In order to reduce the risks for ITER Plasma Facing Components (PFCs), it is proposed to equip Tore Supra with a full tungsten divertor, benefitting from the unique long pulse capabilities, the high installed RF power and the long experience with actively cooled high heat flux components of the Tore Supra platform. The transformation from the current circular limiter geometry to the required X-point configuration will be achieved by installing a set of copper poloidal coils inside the vacuum vessel. The new configuration will allow for H-mode access, providing relevant plasma conditions for PFC technology validation. Furthermore, attractive steady-state regimes are expected to be achievable. The lower divertor target design will be closely based on that currently envisaged for ITER (W monoblocks), while the upper divertor region will be used to qualify the main first wall heat sink technology adopted for the ITER blanket modules (CuCrZr copper/stainless steel) with a tungsten coating (in place of the Be tiles which ITER will use). Extended plasma exposure will provide access to ITER critical issues such as PFC lifetime (melting, cracking, etc.), tokamak operation on damaged metallic surfaces, real time heat flux control through PFC monitoring, fuel retention and dust production.

Thermal performance of a carbon fiber composite material heat sink in an FC-72 thermosyphon

This study analyzes the use of a carbon fiber epoxy heat sink for evaporator surface enhancement in a FC-72 thermosyphon. The pin-fin heat sink features 945 small-cross-section (1.27 mm by 0.965 mm) fins fabricated with an integral base plate. These fins have a high thermal conductivity (500 W/m K) along the length of the fin. The influence of heat load, thermosyphon fill volume, and condenser operating temperature on the overall thermal performance is examined. The results of this experiment provide significant insight into the possible implementation and potential benefits of carbon-fiber heat sink technology in two-phase flow leading to significant improvements in thermal management strategies for advanced electronics.

Temperature Control at DBS Electrodes Using Heat Sinks: Experimentally Validated FEM Model of DBS Lead Architecture

There is a growing interest in the use of Deep Brain Stimulation (DBS) for the treatment of medically refractory movement disorders and other neurological and psychiatric conditions. The extent of temperature increases around DBS electrodes during normal operation (joule heating and increased metabolic activity) or magnetic coupling (e.g., MRI) remain poorly understood, and methods to mitigate temperature increases are actively investigated. Indeed, brain function is especially sensitive to the changes in temperature including neuronal activity, metabolic functions, blood-brain barrier integrity, molecular stability, and viability. We developed technology to control tissue heating near DBS leads by modifying the thermal properties of lead materials. A micro-thermocouple was used to measure the temperature near DBS electrodes immersed in a saline bath. 3387 and 3389 Leads were energized using Medtronic DBS stimulators. The RMS of the driving voltage was monitored. Peak steady-state temperature was determined under different RMS values. A micro-positioning system was used, which allowed the generation of temperature field map. We developed and solved a finite element method (FEM) bio-heat transfer model of DBS incorporating realistic DBS lead architecture. The model was first validated using the experimental results (by matching saline thermal conductivity and electrical conductivity) and was then applied to develop methods to control temperature rises in the brain using heat-sink technology. Experimental measurements are consistent with theoretical predictions including: 1) Peak temperature increases directly with the RMS square of the applied voltage, such that different waveforms with the same RMS induce the same peak temperature rise; 2) Peak temperatures increases with contact proximity such the maximal temperature rise was observed using adjacent contacts of lead 3389; 3) Temperature decayed over ∼2 mm distance away from energized contacts. FEM results demonstrated the central role of lead materials (material properties and geometry) in controlling temperature rise by conducting heat: namely by acting as passive heat sinks. We report that the relatively high thermal conductivity of exiting DBS lead wiring affects the temperature field, indicating the importance of detailed lead architecture. We then demonstrate how modifying lead design to optimize heat conduction can effectively control temperature increases; the manifest advantages of this approach over complimentary heat-mitigation technologies is that heat-sink controls include: 1) insensitive to the mechanisms of heating (e.g., nature of magnetic coupling); 2) does not interfere with device efficacy (e.g., the electric fields induced in the tissue during stimulation are unaffected); and 3) can be practically implemented in a broad range of implanted devices (cardiac/neuro-prothethics, pumps...) without modifying device operation or implant procedure.

Thermacore to develop active heat sink technology

Thermacore to develop active heat sink technology

High-performance millimeter-wave superlattice electronic devices

Negative differential resistance devices, based on two similar AlAs/GaAs superlattice structures, were fabricated using a standard selective etching and integral heat sink technology and evaluated in a resonant-cap full-height WR-15 waveguide cavity. Devices from both superlattice structures generated comparable output powers in the fundamental mode at 59–71 GHz. The best devices yielded >80 mW (with corresponding dc-to-RF conversion efficiencies of >4.5%) around 63 GHz. In a second-harmonic mode, these devices yielded up to 14 mW (1%) at 133 GHz. Higher harmonic frequencies were also observed with powers of >0.4 mW at 190 GHz and >0.1 mW at 260 GHz. The highest observed dc-to-RF conversion efficiency was 5.1% at 62.8 GHz.

Copper‐filled macroporous Si and cavity underneath for microchannel heat sink technology

AbstractThermal management in ICs becomes essential as integration density and total power consumption increase. The use of microchannels in high power density electronics cooling is a well‐known technique for heat transfer. In this work we developed Cu‐filled macroporous Si channels with a Cu‐filled cavity underneath, which may be used as heat sinks in high power density electronics cooling. Macroporous Si is formed by electrochemical dissolution of bulk Si, while pore filling with copper is achieved by electro‐deposition. Using appropriate design, the resulting composite material may be fabricated on selected areas on the silicon substrate for use as heat sink on Si. The surface area is defined by patterning. The macroporous Si structure is composed of either randomly distributed pores or pores arranged in two‐dimensional (2‐D) arrays, fabricated by pre‐patterning the Si surface before anodization so as to form pore initiation pits. The pore size in this work was 5μm, while the porous layer and the cavity underneath had both a thickness of 40 μm. Copper deposition proceeds first by filling the micro‐cavity underneath the porous layer. This is achieved by linearly increasing the applied potential during electro‐deposition. After full Cu‐filling of the cavity, pore filling starts from the bottom of each pore and proceeds laterally, while no nucleation takes place on pore wall. In this way, homogeneous copper wires within pores may be fabricated. The Cu/Si composite material is appropriate for forming channels with improved heat transfer within the Si wafer. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

THE ADVANTAGES OF EVAPORATION IN MICRO-SCALE CHANNELS TO COOL MICROELETRONIC DEVICES

In this paper, the importance of the development of new high power density thermal management systems for electronic devices is assessed. It is described the new heat sink technologies under development to be used in the cooling of microprocessors. The main difficulties to be overcome before the spreading of one specific heat sink configuration are identified. At the end, it is concluded that a heat sink based on flow boiling in micro-scale channels is the most promising approach.

Modeling of Fluid Flow and Heat Transfer in a Copper Based Heat Sink Application

With the trend towards increasing the speed of processors in smaller sized of computers, there has been considerable interest in heat sink technologies with higher levels of performance and further miniaturization. This work addresses the fundamental heat transfer augmentation question of how to design a copper-based heat sink, when the overall dimensions of the bottom plate or fan are specified. A three-dimensional finite-volume model has been developed and applied to investigate flow and conjugate heat transfer in the copper-based heat sink. The model was produced with the commercial program FLUENT, which allows this nonlinear, highly turbulent problem to be simulated using the k-ε turbulence model. The theoretical model developed is validated by comparing the model predictions with available experimental data. The thermal performance and temperature distribution for the heat sink were analyzed and a procedure for optimizing the geometrical design parameters based on less space occupation and more efficient heat transfer coefficient is presented. Several design examples with different types of cooling methods and manufacturing processes have been analyzed. The reliability and effectiveness in heat spreading of those has been compared. It has been shown that the copper-based heat sink with louvered fins (case No.3) has an optimum design configuration.

Acoustic wave corrected current-voltage characteristics of GaAs-based structures with Schottky contacts

The effect of ultrasonic treatment (UST) on the current-voltage (I-U) characteristics of Au-TiBx-n-n +-GaAs diode structures has been studied. Upon acoustic loading with an intensity below 2 W/cm2, the character of the UST-induced changes in the reverse branches of I-U curves depends on the predominating mechanism of current transfer. UST at a power density above 2.5 W/cm2 increases the reverse current by one or two orders of magnitude. It is shown that UST favors a significant increase in the homogeneity of the characteristics of devices manufactured using integral heat sink technology.

High-power 1.9-μm diode laser arrays with reduced far-field angle

High-power 1.91-mum (AlGaIn)(AsSb) quantum-well diode laser single emitters and linear arrays with improved waveguide design were fabricated and characterized. The use of a rather narrow waveguide core results in a remarkable low fast axis beam divergence of 44deg full-width at half-maximum. For single emitters, a continuous-wave (CW) output power of nearly 2 W has been observed. We have achieved 16.9 W in CW mode at a heat sink temperature of 20degC. The efficiencies of more than 25% are among the highest values reported so far for GaSb-based diode lasers, and allow the use of passively cooled and, thus, less expensive heat sink technologies

Economic and Performance Evaluation of Heat Sink Options in Combined Cycle Applications

This paper is a guideline to selecting the most appropriate technology for the power plant heat sink based on water availability, site location, and wastewater disposal requirements. The paper discusses wet as well as dry cooling systems and evaluates the impact of the heat sink technology on the performance and cost of combined cycle power plants. Cogeneration applications and cycling plant operations are also considered. For each proposed option, the performance, relative costs, and noise issues will be presented.