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Thermal management is one of the main challenges for the future of electronics 1 – 5 . With the ever-increasing rate of data generation and communication, as well as the constant push to reduce the size and costs of industrial converter systems, the power density of electronics has risen 6 . Consequently, cooling, with its enormous energy and water consumption, has an increasingly large environmental impact 7 , 8 , and new technologies are needed to extract the heat in a more sustainable way—that is, requiring less water and energy 9 . Embedding liquid cooling directly inside the chip is a promising approach for more efficient thermal management 5 , 10 , 11 . However, even in state-of-the-art approaches, the electronics and cooling are treated separately, leaving the full energy-saving potential of embedded cooling untapped. Here we show that by co-designing microfluidics and electronics within the same semiconductor substrate we can produce a monolithically integrated manifold microchannel cooling structure with efficiency beyond what is currently available. Our results show that heat fluxes exceeding 1.7 kilowatts per square centimetre can be extracted using only 0.57 watts per square centimetre of pumping power. We observed an unprecedented coefficient of performance (exceeding 10,000) for single-phase water-cooling of heat fluxes exceeding 1 kilowatt per square centimetre, corresponding to a 50-fold increase compared to straight microchannels, as well as a very high average Nusselt number of 16. The proposed cooling technology should enable further miniaturization of electronics, potentially extending Moore’s law and greatly reducing the energy consumption in cooling of electronics. Furthermore, by removing the need for large external heat sinks, this approach should enable the realization of very compact power converters integrated on a single chip. Cooling efficiency is greatly increased by directly embedding liquid cooling into electronic chips, using microfluidics-based heat sinks that are designed in conjunction with the electronics within the same semiconductor substrate.

The focus of this article is on topology optimization of heat sinks with turbulent forced convection. The goal is to demonstrate the extendibility, and the scalability of a previously developed fluid solver to coupled multi-physics and large 3D problems. The gradients of the objective and the constraints are obtained with the help of automatic differentiation applied on the discrete system without any simplifying assumptions. Thus, as demonstrated in earlier works of the authors, the sensitivities are exact to machine precision. The framework is applied to the optimization of 2D and 3D problems. Comparison between the simplified 2D setup and the full 3D optimized results is provided. A comparative study is also provided between designs optimized for laminar and turbulent flows. The comparisons highlight the importance and the benefits of full 3D optimization and including turbulence modeling in the optimization process, while also demonstrating extension of the methodology to include coupling of heat transfer with turbulent flows.

The heat generation of electronic devices is increasing dramatically, which causes a serious bottleneck in the thermal management of electronics, and overheating will result in performance deterioration and even device damage. With the development of micro-machining technologies, the microchannel heat sink (MCHS) has become one of the best ways to remove the considerable amount of heat generated by high-power electronics. It has the advantages of large specific surface area, small size, coolant saving and high heat transfer coefficient. This paper comprehensively takes an overview of the research progress in MCHSs and generalizes the hotspots and bottlenecks of this area. The heat transfer mechanisms and performances of different channel structures, coolants, channel materials and some other influencing factors are reviewed. Additionally, this paper classifies the heat transfer enhancement technology and reviews the related studies on both the single-phase and phase-change flow and heat transfer. The comprehensive review is expected to provide a theoretical reference and technical guidance for further research and application of MCHSs in the future. The studies on microchannel heat sinks for electronics cooling are reviewed comprehensively. The main research areas of interest for microchannel heat sinks are classified. The studies on both single-phase and phase-change flow cooling are reviewed. The characteristics, application conditions and shortcomings of microchannel heat sinks with different structures, working fluids, materials and some other influencing factors are introduced. The prospects for and development trends of microchannel heat sinks are revealed based on the overall review and analysis.

The current two-dimensional (2D) numerical study presents the melting phenomenon and heat transfer performance of the nanocomposite phase change material (NCPCM) based heat sink. Metallic nanoparticles (copper: Cu) of different volume fractions of 0.00, 0.01, 0.03, and 0.05 were dispersed in RT–28HC, used as a PCM. Transient simulations with conjugate heat transfer and melting/solidification schemes were formulated using finite–volume–method (FVM). The thermal performance and melting process of the NCPCM filled heat sink were evaluated through melting time, heat storage capacity, heat storage density, rate of heat transfer and rate of heat transfer density. The results showed that with the addition of Cu nanoparticles, the rate of heat transfer was increased and melting time was reduced. The reduction in melting time was obtained of − 1.36 % , − 1.81 % , and − 2.56 % at 0.01, 0.03, and 0.05, respectively, compared with 0.00 NCPCM based heat sink. The higher heat storage capacity enhancement of 1.87 % and lower reduction of − 7.23 % in heat storage density was obtained with 0.01 volume fraction. The enhancement in rate of heat transfer was obtained of 2.86 % , 2.19 % and 1.63 % ; and reduction in rate of heat transfer density was obtained of − 6.33 % , − 21.05 % and − 31.82 % with 0.01, 0.03, and 0.05 volume fraction of Cu nanoparticles, respectively. The results suggest that Cu nanoparticles of 0.01 volume fraction has the lower melting rate, higher heat storage capacity and heat transfer rate, lower heat storage density and heat transfer rate density which is preferable for passive cooling electronic components.

Microchannel cooling is often the preferred choice for compact heat sinks. However, widely adopted topology optimisation (TO) techniques such as density-based and level-set methods often struggle to generate very thin channel strips unless maximum length scale constraints are imposed and very fine meshes are employed. To address this limitation, multi-scale design methodologies have emerged. This paper builds upon recent advances in de-homogenisation techniques to contribute to the multi-scale design of microchannels for cooling applications. We start by selecting a single-class microstructure and employ numerical homogenisation to build an offline library. This library is then fed in online macro-scale topology optimisation, where both microstructure parameters and local orientation fields are optimised. By using a sawtooth-function-based mapping, the de-homogenised results capture fine details across different length scales through a unique homogenised design. Our findings show that the generated microchannels outperform conventional pillar arrays, offering valuable insights for heat sink designers. Additionally, imperfections observed in the de-homogenised results serve as benchmarks for future improvements, addressing concerns related to modelling accuracy, manufacturability, and overall performance enhancements.

The liquid-cooled heat sink is an effective and robust cooling device and has been widely used in the industry. The fluid-thermal topology optimization approaches have been adopted for the heat sink design by many researchers. However, none of these works considered the optimization of heat source distribution. This work focuses on the synergic design of the cooling channels and the layout of heat sources with diverse intensities. A hybrid topology optimization approach is adopted, in which the channels are implicitly described with pseudo-density while the heat sources are considered as moving components. The maximum temperature of the system is taken as the objective and constrained by the fluid power dissipation. In order to avoid unrealistic designs such as suspended structures, the stiffness of the structure is considered as a constraint. Considering when heat sources have diverse intensities, the initial locations of the heat sources could significantly affect the optimal result. Aiming at this problem, a heuristic algorithm that can redistribute the heat sources efficiently during the optimization process by exchanging their locations is developed. The topology optimization is performed with a parallel solver developed in Open Field Operation And Manipulation (OpenFOAM) framework. The numerical tests show that the influence of the heat source distribution on the cooling performance could be even higher than the cooling channel design, and the synergic topology optimization method is an effective way to design high-performance heat sink.

Thermoelectric coolers are preferred in many areas because of their simple mechanism and no need for a refrigerant. In this study, an air-to-water mini thermoelectric cooler system was designed and produced. Experiments were performed by placing different numbers of thermoelectric modules on the liquid-cooling heat sink and applying different voltages. The cooling capacity and COP values of the system under different operating conditions were analyzed and discussed. In addition, the effect of fluid flow rate on system performance and temperature difference between inlet and outlet sections has been presented. The heat transfer and flow behavior of the fluid in the liquid-cooling heat sink were determined using CFD simulation methods. Moreover, the heat loss from the system was tried to be reduced by using extra foam insulation and the results were compared with single foam and the effect of the insulation on the temperature drop inside cooler was discussed. At 0.011 kg s −1 mass flow rate and 12 V voltage conditions, when the number of TE modules is increased from 1 to 3 in the TE cooler, a maximum increase of 35% in cooling load is obtained. Also, if the cases with 3 TE modules and 0.011 kg s −1 flow rate are compared in terms of cooling load, 12 V has 80% higher cooling load than 4 V. According to the numerical results, flow structures that negatively affect the heat transfer interactions and reduce the cooling performance of the TE cooler have been determined in the liquid-cooled heat exchanger. Additionally, a significant decrease in the temperature of the cooling chamber has also been achieved with additional insulation.

In the modern digital world, electronic devices are being widely employed for various applications where thermal performance represents a significant technical challenge due to continued miniaturization, high heat generated in the system, and non-uniform high-temperature causing failure. Phase change materials (PCMs) owing to the immense heat of fusion are primarily considered for thermal management, but their insulating properties hedge their applications in electronics cooling. Nano-enhanced phase change materials (NePCMs) have the ability to improve the thermal conductivity of PCM, decrease system temperature and escalate the operating time of devices. Accordingly, the current study focused on the experimental investigations for the thermal performance of three heat sinks (HS) with different configurations such as a simple heat sink (SHS), a square pin-fins heat sink (SpfHS), and Cu foam integrated heat sink (CufmHS) with various alumina nanoparticles mass concentrations (0.15, 0.20 and 0.25 wt%) incorporated in PCM (RT-54HC) and at heat flux (0.98–2.94 kW/m2). All HSs reduced the base temperature with the insertion of NePCM compared to the empty SHS. The experimental results identified that the thermal performance of CufmHS was found to be superior in reducing base temperature and enhancing working time at two different setpoint temperatures (SPTs). The maximum drop in base temperature was 36.95%, and a 288% maximum working time enhancement was observed for CufmHS. Therefore, NePCMs are highly recommended for the thermal management of the electronic cooling system.

In electronic components, systems for thermal management considerably affect the components’ performance. Rapid advances in computer processing unit chips have led to substantial increases in their power consumption and heat generation. Many researchers have focused on studying the use of phase change materials (PCMs) to stabilize the temperature of electronic components. These materials regulate the temperature by absorbing latent heat during phase transitions. However, despite their high latent heat capacity, the low thermal conductivity of PCMs results in prolonged phase change duration time. In order to address this limitation, both industry and academia have directed significant attention toward enhancing the heat transfer efficiency of PCMs. This study investigates the effect of the volume fraction of PCM, specifically paraffin, on the thermal performance of heat sinks used in electronic components. The research compares the temperature profiles of heat sinks not equipped with fins, with circular pin fins, and with square pin fins under various PCM volume fractions to evaluate their performance while a high latent heat PCM was used. By way of designing different heat sinks, PCM volume fractions, and different power levels to investigate the final base temperature, PCM temperature distribution uniformity, and Stefan number (Ste). When the fin volume fraction was fixed at 9% for heat sink equipped with circular pin fins, and with square pin fins, the heat sink equipped with circular pin fins exhibited superior thermal performance to the square fins and no fins heat sinks. Moreover, among all examined heat sinks that equipped with circular pin fins exhibited the lowest base temperature, highest heat transfer efficiency, and smallest rate of increase in base temperature. In addition, the higher PCM volume fraction at 0.9 shows the lower base temperature. For all designed heat sinks, the cooling effect of base temperature was achieved by adding PCM which is stronger when the heat flux was 1.6 and 2.4 kW/m 2 than 0.8 kW/m 2 . The improvement achieved in the cooling performance with an increase in φ was greater at a higher heat flux. On the other hand, at a heat flux of 2.4 kW/m 2 and PCM volume fraction of 0.9, the heat sink equipped with square pin fins exhibits better PCM temperature distribution uniformity than the heat sink equipped with circular pin fins and with no fins, and measured points maximum temperature differences are 3.75, 6.30, and 9.75°C, respectively. Furthermore, this study examined how the Ste affected the time it took to reach different temperatures in the three designed heat sinks. For all three designs, the time it took to reach different temperatures decreased with an increase in the Ste. When the Ste was 12.55, among the designed heat sinks, that equipped with square pin fins was the slowest in reaching 50°C. However, at Stes of 25.10 and 37.65 that equipped with circular pin fins was the slowest in reaching 50°C. Moreover, at Stes of 25.10 and 37.65 that equipped with circular pin fins was the slowest in reaching 55 and 60°C.

The uneven temperature distribution resulting from thermal stresses in heat sinks is a significant issue in modern electronic devices. This numerical investigation utilizes fluid to analyze the cooling, flow, and heat transfer characteristics of eight different heat sink designs. These include pin–fin heat sinks with circular, triangular, square, and hexagonal cross-sections, as well as their perforated versions. The results show that the thermal resistance range for all geometries was between R th  = 0.29 and 0.51 K W −1 . The circular cross-section pin structure was found to be the most efficient in terms of thermal resistance, while the triangular perforated structure was the least efficient. The narrow and low temperature distribution indicates a high cooling potential for the heat sink. It has been observed that the temperature range studied is between 308.732 and 315.273 K. The circular cross-section pin structure is most efficient in terms of homogeneous distribution between 308.73 and 311.306 K. The pin-type structure with a square cross-section attained the maximum Performance Evaluation Criteria (PEC) of 1.1872 at P  = 689 Pa, while the pin-type structure with a triangular cross-section attained the lowest PEC of 0.67 at P  = 2750 Pa. The investigation revealed that, in relation to PEC, perforated structures had superior performance compared to other pin designs, except for the square-section pin structure. This research found that measuring the efficiency of a heat sink based just on thermal resistance or average temperature distribution is not enough; the PEC criteria must also be taken into account.