Manifold Microchannel Research Articles

Numerical and experimental study on manifold-distributed jet microchannel with micro-pin-fins

Traditional parallel microchannels are inadequate for managing the thermal requirements of newer, large-area and high-heat-flux chips. This inadequacy arises from its high flow resistance and poor temperature uniformity. Therefore, A novel manifold microchannel heat sink combining manifold inlet/outlet structures, distributed array jets, and micro pin-fins is introduced. Numerical simulations and experimental methods were employed to investigate the flow and heat transfer performance of the heat sink. Experimental results show that, with an average heat flux density exceeding 330 W/cm2 and a total power of 2500 W, the average chip temperature remains below 70 °C, ensuring efficient heat dissipation. Secondary impingement occurs at sufficiently low jet chamber heights, resulting in an increase of 3 times in the average Nusselt number for a smooth base plate. For the micro-pin-finned surface, it is shown that the presence of micro-pin-fins is not necessarily conducive to heat transfer enhancement. A critical volume fraction of micro-pin-fins (critical fin-ratio) exists where the obstructive effect and enhancement effect balance each other out. This value is influenced by multiple parameters. Finally, a novel relationship for predicting the average Nusselt number of jet impingement was proposed, with an average absolute error of less than 15 %. This series of investigations addresses the existing gaps in research on manifold-distributed array jet heat sinks and provides a meticulous theoretical foundation for the design and optimization of heat sinks facing the high-power chips.

Hybrid artificial neural networks-based approaches predicting the heat transfer and flow characteristics of manifold microchannels

Aiming at meeting the requirement of high heat flux electronics cooling, the geometric complexity of manifold microchannels as an energy-saving technique has been increasing rapidly. It is well worth exploring optimal prediction models for the heat transfer and flow characteristics of manifold microchannels to reduce computing resources and time costs in the optimization process. In this paper, hybrid prediction approaches based on artificial neural networks are proposed for manifold microchannels. Four optimization algorithms, namely, genetic algorithm, particle swarm optimization algorithm, artificial hummingbird algorithm, and zebra optimization algorithm were adopted to enhance the prediction performance. Initially, all prediction models were trained and tested by a numerical database including six input parameters, and the thermal resistance and pumping power were taken as the target outputs. Compared to the original method, hybrid prediction models show higher accuracy and reliability on the numerical data with regression coefficients beyond 0.987. The prediction model optimized by the artificial hummingbird algorithm shows the best performance with the mean average error for thermal resistance and pumping power decreased by 88.7% and 81.4% respectively. Additionally, the runtime of all prediction models is compared and the model optimized by the zebra optimization algorithm takes the longest time, but is still two orders of magnitude shorter than that of the traditional simulation method. Finally, the generalizability of all prediction models is further validated by a database amassed from six experimental studies on manifold microchannels. The results showed that three hybrid models can provide accurate outputs with regression coefficients beyond 0.84 which differs from the poor prediction of the original method. The model optimized by the zebra optimization algorithm shows superior prediction performance for six individual studies, two fluids, three fin shapes, and wide flow rate conditions. The trained hybrid prediction models in this study perform higher accuracy and can be cost-effective and reliable prediction tools for the rapid optimization process of various manifold microchannel applications.

Advancing cryogenic electronic cooling: A case study on embedded manifold microchannels in micromachined Joule-Thomson coolers

Thermal management plays a crucial role in the performance of electronic devices. For devices operating at room temperatures, manifold microchannels (MMCs) are essential for heat dissipation in heat sinks due to their low thermal resistance and pressure drop. However, their application in cryogenic electronic devices to enhance thermal performance has been largely unexplored. Herein, we integrated manifold microchannels into the evaporator of a micromachined Joule-Thomson (MJT) cooler to improve its cooling performance. The results show a notable reduction in the minimum cooling temperature from 105.0 K to 95.3 K, accompanied by an approximate 20 % increase in maximum cooling power. Furthermore, the coefficient of performance (COP) exhibits a rise of over 20 %. These findings underscore the feasibility and effectiveness of using MMCs in cryogenic electronic devices.

Experimental investigation of heat transfer and pressure drop in copper manifold microchannel heat sinks

Over the past decade, various two-phase cooling solutions have been implemented to dissipate power in high heat flux electronic components. The manifold microchannel heat sink is an efficient thermal management solution that reduces heat resistance while also limiting the pumping power. However, there is limited work available on small form factor manifold microchannels with traditional heat sinking materials like copper. In this study, an experimental investigation is conducted to evaluate the heat transfer and pressure drop performance of copper manifold microchannel heat sinks using an environmentally friendly refrigerant, R1233zd(E), as the working fluid. A microchannel plate and a manifold plate, both made of oxygen-free copper, are sandwiched together to form the manifold microchannel test sample assembly. To compare the effects of geometric parameters, a total of six manifold microchannel test samples are investigated, including two types of manifold plates and three types of microchannel plates. The experiments are performed with refrigerant mass flow rates ranging from 5 to 15 g/s and inlet subcooling temperatures ranging from 3 to 10 K. The heat transfer coefficient increases with a decreasing number of manifolds and with an increase in the number and width of the microchannels. The pressure drop decreases in configurations with more microchannels, more manifolds, and larger microchannel widths. Compared to traditional microchannels, manifold microchannels significantly reduce the total pressure drop. However, their heat transfer performance at higher heat flux conditions is limited by the trapped bubbles phenomena. In comparison to traditional microchannels, manifold microchannels demonstrate much higher performance in dissipating the same amount of heat flux while limiting pumping power, as indicated by the COP.

An innovative manifold microchannel heat sink for thermal management of high-power chips with multiple hotspots

In this study, we propose an innovative manifold microchannel heat sink (MMCHS) featuring perforated baffle structures, which is specifically engineered to address the thermal management challenges associated with chips that exhibit multiple hotspots. By enhancing the conventional Z-shaped MMCHS, we designed a cost-effective and efficient cooling solution tailored specifically for precise temperature regulation across multiple hotspots. We employed numerical simulation techniques to analyze the flow dynamics and heat transfer properties of the optimized manifold microchannel heat sink (OMMCHS) across various baffle configurations and perforation densities. The findings reveal that the OMMCHS significantly outperforms the traditional Z-shaped MMCHS, establishing it as a superior option for cooling of high-power chips with multiple hotspots. Notably, the OMMCHS configuration equipped with I-type baffles and a 50% perforation rate yields the most favorable results, ensuring temperature homogeneity across the hotspots at an inlet velocity of 1.9 m/s. Compared to the MMCHS, the OMMCHS reduces pump power consumption by up to 77.8% while maintaining the same peak temperature, highlighting its efficiency and effectiveness in thermal management.

Integrated manifold microchannels and near-junction cooling for enhanced thermal management in 3D heterogeneous packaging technology

The rapid advancement in electronic chip technology is driving the evolution of highly integrated and high-power configurations, which in turn imposes greater demands on thermal management. This study presents a novel approach to address the thermal management challenges associated with high-density integrated chips. By incorporating the near-junction cooling method into silicon-based chips, the thermal resistance during heat conduction is effectively reduced. To further enhance heat dissipation efficiency, we integrate manifold microchannels and near-junction cooling into an aluminum nitride ceramic substrate, creating a heterogeneous three-dimensional integrated chip. To verify the effectiveness of our approach, a thermal test chip and an aluminum nitride substrate with a manifold structure are meticulously prepared and packaged for experimental testing. Remarkably, the experimental results demonstrate that the heterogeneous integrated chip, featuring manifold microchannels, achieves an impressive heat dissipation capacity of 700 W/cm2 under normal operating temperature conditions. Additionally, sensitivity analysis and multi-objective optimization approach were employed, utilizing the Response Surface-Genetic Algorithm П(NSGAП), to optimize the manifold microchannels in the heterogeneous integrated chip. The optimization process yields significant improvements, reducing the total thermal resistance of the chip by 13.6 % and the maximum pressure drop by 68.5 %. These findings provide valuable theoretical insights and guidance for the thermal design of high heat flux integrated chips, and contribute to advance the design and development of high-performance integrated circuit systems.

Numerical study on a new manifold ring-shaped microchannel structure for circular heat source with excellent temperature uniformity

The manifold microchannel heat sink shows great potential for cooling high-heat-flux electronic equipment owing to its exceptional thermal and flow performance. A new manifold ring-shaped channel design is introduced to improve the temperature uniformity for circular heat sources. A comparative analysis of the manifold straight channel, radial expansion channel and manifold ring-shaped channel designs is conducted based on the same heating area under equal mass flow conditions by numerical investigation using single-phase de-ionized water. The findings indicate that the newly proposed manifold ring-shaped channel design exhibits a lower maximum temperature, a lower average temperature, a better temperature uniformity and a smaller pressure drop in comparison to the straight channel and radial channel designs. Specifically, at a mass flow rate of 2.5 g/s, the ring-shaped channel design demonstrates a 71.4 % and 45.4 % reduction in the temperature difference between the maximum temperature and the minimum temperature of the heating surface, and the coefficient of performance is enhanced by 458.2 % and 169.7 % when compared to the straight channel and radial channel designs, respectively. Additionally, three improved designs based on the original manifold ring-shaped channel design are proposed to further enhance fluid flow distribution in the ring-shaped channel design. The results reveal that all three manifold ring-shaped channel optimizations further lower the maximum temperature, the average temperature and the temperature difference. Notably, the improved case3 exhibits the best thermal and hydraulic performances among all structures. When compared to straight channel and radial channel designs, the improved case3 demonstrates an 86.9 % and 75.0 % reduction in the temperature difference, and an increase of 201.2 % and 523.4 % in coefficient of performance under the equal mass flow comparison basis. A heat flux of 1200 W/cm2 can be dissipated at 6 g/s when the maximum temperature rise is kept below 60 K, with a pressure drop of 38 kPa.

Single-phase and flow boiling heat transfer characteristics in staggered finned manifold microchannel heat sink

The investigation of staggered finned manifold microchannel (MMC) for addressing thermal management challenges in high heat flux electronic devices presents promising insights. The research indicates that staggered finned MMCs exhibit superior heat transfer characteristics in comparison to traditional rectangular microchannels, particularly under single-phase flow conditions. When staggered finned microchannels reduce the maximum temperature of the heating surface by around 10 K, the pressure drop is reduced by 1.3 kPa. Notably, as the heat flux escalates, the advantages of staggered finned MMCs become increasingly pronounced, while higher flow rates lead to a gradual diminishment of these advantages. Furthermore, in scenarios involving flow boiling with low heat flux and high flow conditions, staggered finned MMCs demonstrate enhanced heat transfer performance over traditional rectangular microchannels. When staggered finned microchannels reduce the maximum temperature of the heating surface by around 3 K, the pressure drop is improved by 1.2 kPa. Moreover, the study underscores that at lower flow rates, staggered finned MMCs experience a reduced pressure drop relative to traditional rectangular microchannels, whereas at higher flow rates, this trend is reversed. These findings carry significant implications for the optimization of thermal management strategies for electronic devices operating under high heat flux conditions.

Thermal-hydraulic performance of an imperfectly bonded ultrathin manifold micro pin-fin channel heat sink

This study numerically investigated the thermal-hydraulic performance of an ultrathin manifold microchannel heat sink (MMHS) and an ultrathin manifold micro pin-fin channel heat sink (MMPF-HS) with gaps between the manifold and microchannel layers. Unlike previous researches, the effect of the presence of gaps on flow distribution and overall heat transfer of MMHS and MMPF-HS was analyzed. The simulation results show that the presence of the gap significantly affect the heat transfer of both heat sinks but have minimal impact on pressure drop. For the MMHS with a gap of 0.05 mm in height, the bypass effect introduced by the gaps makes the uneven flow distribution worse and causes the formation of low-speed vortexes, leading to a 25.5% increase in the average temperature and 2.1-fold increase in the temperature non-uniformity of the heating surface. MMPF-HS is more effective in mitigating the effect of gap on temperature non-uniformity compared to the original MMHS due to the structural optimization. For the MMPF-HS with a 0.05 mm height gap, the average surface temperature rises from 34.3 to 40.9 °C, and the temperature non-uniformity increases from 1.1 to 5.5 °C, which remain significantly lower than those of the original MMHS without a gap.

Multi-objective parameter optimization design of tapered-type manifold/variable cross-section microchannel heat sink

Manifold microchannel heat sinks (MMCHS) have been widely used in the thermal management of high heat flux electronic devices. To improve the temperature uniformity of MMCHS and reduce the hot spot temperature, a tapered-type manifold/variable cross-section microchannel heat sink (TMVC-MCHS) is proposed in this study. Key parameters affecting the heat transfer performance of TMVC-MCHS were first investigated numerically. The results indicate that the width inclination ratio (αw,in) of the inlet manifold has a greater influence on the coolant flow distribution than the height inclination ratio (αh,in), with a ratio of more than 2.5. In addition, the microchannel inclination (β) and width ratio (ε) affect significantly the fluid flow and heat transfer. To further improve the cooling effect of the heat sink, this study adopted XGBoost and multi-objective genetic algorithm (NSGA-II) to optimize the structure. The maximum temperature of the substrate (Tmax) and the total pressure drop (ΔP) are the optimization objectives. Besides, the compromise solution (αw,in = 0.40, β = 0.63 and ε = 0.52) was determined by TOPSIS combined with the entropy weight method which was validated by the CFD method with an error margin of only 3 %. Finally, Compared to MMCHS, the temperature field distribution uniformity of TMVC-MCHS is significantly improved. The maximum bottom surface temperature is drastically reduced from 337.79 K to 320.01 K, and the temperature difference is reduced from 17.5 K to 3.5 K, at the cost of only a 3.5 kPa pressure rise. For inlet flow rates ranging from 1 m/s to 2.5 m/s, the TMVC-MCHS exhibits a hydrothermal performance factor (PEC) improvement of over 35 %, indicating superior comprehensive performance.

Topological and multi-objective optimization of single-phase heat transfer and energy efficiency using manifold micro-channels for high-power electrics cooling

To achieve energy-efficient cooling of high-power electrics, present work demonstrates combined methods using topological design and multi-objective optimization to reconstruct manifold micro-channels (MMC). The micro-channel domain is first topologized by density-based method under pressure drop and energy dissipation constraints. The multi-objective optimization is subsequently applied to optimize structure and operating parameters of reconstructed MMC using kriging model and genetic algorithm. The simulation results show that favorable thermal performance is obtained in the topological MMC with branch-channels, pin fins and root-channels, increasing average heat transfer coefficient by 19.4 % compared to conventional MMC. For the optimal flow rate, the lowest total thermal resistance (Rtotal) of 0.17 KW−1 is obtained for the optimized-topological MMC at a pumping power (Pp) of 9.53 mW, meanwhile the maximum temperature-rise is decreased by 15.2K. Furthermore, an extensive benchmark of different single-phase micro-fluidic cooling technologies is performed. For an extremely low Rtotal of 0.2 KW−1, present optimized-topological MMC only requires Pp of 3 mW, which is 11.7 times, 26.7 times and 70 times lower than that of conventional MMC, pin-fin and strip-fin micro-fluidic systems. This superior hydro-thermal performance successfully manages the heat flux of 100 W/cm2 to 400 W/cm2 with cooling coefficient of 104 to 107, significantly outperforming other micro-fluidic cooling technologies.

Self-driven manifold microchannel heat sink for cooling electronics

The advancement of passive, compact, and lightweight thermal management technology for high-power chips is essential for the stable and efficient operation of the next generation of electronic devices. A novel self-driven heat sink based on embedded manifold microchannel heat dissipation technology is proposed, which uses capillary force as the driving force to replace the pump, and minimize pressure drop and thermal resistance between the heat sink and heat source. This design of the embedded self-driven manifold microchannel heat sink allows for the integration and miniaturization of the heat sink and the chip heat source. Through Micro Electromechanical Systems technology, an experimental sink with microchannels with a high aspect ratio was fabricated. A theoretical model is constructed to analyze the influence of the width and depth of the microchannel on the limit heat flux, and the correctness of the model is verified by experiments. The results indicate that the width has a more significant impact on the limit heat flux compared to the depth. An optimal width of 6.5 μm is identified. As the depth increases, the influence of depth on the limit heat flux diminishes. By conducting theoretical calculations on the embedded self-driven manifold microchannel heat sink, it was determined that the device using HFE7100 as the working fluid demonstrates a wider heat load range than ethanol and acetone, and the limit heat flux can reach 41.5W/cm2.

One-dimensional model of manifold microchannels for embedded cooling: Prediction of thermal performance and flow non-uniformity

A one-dimensional model has been developed to accurately predict the thermal performance and flow non-uniformity of the manifold microchannels (MMC) for embedded liquid cooling. The model consists of one-dimensional governing equations derived from the integral relations of momentum and energy over appropriately-defined two separate control volumes. To validate the model, a series of 3-D numerical simulation is conducted over the wide ranges of the Reynolds number (Rem,in) at the manifold inlet from 560 to 3190, the dimensionless hydraulic flow length (x+) from 0.012 to 0.123, and the dimensionless thermal flow length (x∗) from 0.002 to 0.023. It is shown that the model provides accurate predictions of the thermal performance and flow non-uniformity (CV) of MMC heat sinks within the root mean square percentage error (RMSPE) of 6% and 26% for 50 data points, respectively. The significant improvement of the prediction accuracy is made over the earlier models with an error reduction of 82%. Finally, a design guideline for the uniform flow distribution is suggested for the first time based on a newly proposed explicit correlation for predicting the flow non-uniformity: the dynamic pressure at the manifold inlet should be kept smaller than the pressure drop across the microchannels.

Optimization of Manifold Microchannel Heat Sink Based on Design of Experiment Method

Abstract The manifold microchannel heat sink (MMCHS) shows high potential to cope with the rapidly increasing power density of electronic devices. It is of significance to search for an optimization method to comprehensively consider multiparameter effects on the performance of microchannel. Here, we have studied the temperature and flow characteristics of the MMCHS via experimental method. Then, the effect of geometric parameters including microchannel aspect ratio (α), hydraulic diameter (Dh), and manifold block numbers (Nm) on the performance of a MMCHS were studied by numerical method. Subsequently, the design of experiment (DOE) method was proposed to optimize the geometric parameters of the MMCHS. The relation of friction coefficient and heat transfer coefficient with respect to the three geometric parameters was gained by the mathematical regression model. The statistically optimized manifold microchannel achieved a 10.0% reduction in temperature rise, 59.9% enhanced in the heat transfer coefficient, and the figure of merit (FOM) of 1.6. Our work shows a novel method to consider the effect of structure parameters on the performance of the manifold microchannel and provides a novel optimization design method for the manifold microchannel.

Liquid metal manifold microchannel heat sink for ultra-high heat flux cooling

Advanced heat dissipation technology is crucial for chip operation and performance utilization. Room temperature liquid metal convection cooling technology has demonstrated its efficacy as a viable approach for addressing high heat flux heat dissipation. However, the smaller specific heat capacity of liquid metal leads to a large temperature rise, hindering the advancement of its cooling technology. To address this, a liquid metal manifold channel structure is proposed to convert the continuous long-range flow into a segmented short-range flow. The good matching between liquid metal and manifold structures is adequately demonstrated through a comparison with alternative coolant and channel structure. The simulation results demonstrate the effectiveness of liquid metal manifold channel cooling in dealing with a heat flux of 1000 W/cm2, ensuring that the maximum temperature of the chip remains below 351.7 K. Moreover, the convective heat transfer coefficient even reaches 106 W/(m2·K), which is ten times larger than that of water conventional microchannel heat sink. Orthogonal experiments analyzed the impact of structural parameters on dissipation performance, including the height of the microchannel, ratio of manifold length to fin length, length of fin in manifold, width of channel, and ratio of fin with to channel width. The height of the microchannel has been identified as the most critical factor. This manifold structure mitigates the inherent limitation of liquid metal's lower specific heat capacity, enabling efficient thermal management for electronic devices under ultra-high heat flux conditions.

Performance Improvement of Z-Type Manifold Microchannel Heat Sink with Novel Fin-Arrangements

The Z-type manifold microchannel heat sinks are mostly used by researchers due to the simple structure and considerable heat transfer performance. In this study, a novel Z-type manifold microchannel heat sink with fins arranged at intervals in an arithmetic sequence is proposed to improve the thermo-hydraulic performance of the conventional Z-type manifold microchannel. The novel feature of the proposed design is the channel widths being in an arithmetic sequence with a negative common difference, which contributes to equalize the flow distribution among the channels. Various fin arrangements with different common differences under the same heat transfer area are numerically investigated to determine the thermo-hydraulic performance. The results show that the fins arranged at intervals in an arithmetic sequence have a great potential in mitigating the flow maldistribution. Compared to the conventional manifold microchannel, the proposed manifold microchannel has better thermal performance without a significant increase in pressure drop.

Experimental study of embedded manifold staggered pin-fin microchannel heat sink

High-heat-flux thermal management of high-power chips in electronic devices is becoming more and more critical. Manifold microchannel heat sink is one of the effective choices. In order to improve the heat dissipation capacity of manifold microchannel heat sink, a silicon-based thermal test chip including staggered pin-fin microchannels is designed and fabricated. Staggered pin-fin microchannels and rectangular microchannels with the same area size are embedded on the opposite side of the silicon-based thermal test chip for liquid-cooled heat dissipation. The experiments are conducted using HFE7100 as the working fluid. The heat transfer performance and the flow characteristic of two distinct microchannel structures are evaluated. It is found that the differences in temperature, convection heat transfer coefficient and pressure drop caused by different microchannel structures are greatly related to the mass flow rate. The heat transfer performance of the staggered pin-fin microchannel heat sink is better than that of the rectangular microchannel heat sink at a larger mass flow rate, but it also brings greater flow pressure drop. The bubble effect caused by the transition from single-phase to two-phase flow in microchannels makes the monotonicity of the convection heat transfer coefficient decrease significantly and the monotonicity of the pressure drop increase significantly. Compared to rectangular microchannel heat sinks, staggered pin-fin microchannel heat sinks reach the two-phase flow at higher heat flux. At the mass flow rate of 5 mL/s and the heat flux of 700 W/cm2, the staggered pin-fin microchannel heat sink can reduce the chip surface temperature by 8 K compared with the chip surface temperature of the rectangular microchannel heat sink.

Numerical investigation and data-driven prediction of flow boiling heat transfer in manifold microchannels with slopes

The manifold microchannels (MMC) with high heat transfer coefficient and low pressure drop has received much attention. Flow boiling heat transfer inside MMC is promising for dissipating heat of high-power devices. In this study, flow boiling heat transfer inside MMC is further numerically studied with slopes added in the upstream and downstream corners of MMC. The results show that downstream slope leads to lower local temperature and thermal resistance by removing the upstream vapor more easily, and upstream slope leads to higher heat flux corresponding to the turning point in the flowing boiling curve by restraining the local high temperature at upstream corner. The combination of the upstream and downstream slopes can reduce the thermal resistance by 5.45% and increase the heat flux related to the turning point by 14.28% compared to the MMC without slopes. A new flow boiling heat transfer correlation considering the slopes is developed with prediction accuracy of mean absolute deviation (MAD) of about 0.05%. An artificial neural network (ANN) is further built to predict the vapor saturation inside the MMC based on the outside temperature at the MMC bottom surface, which presents high accuracy of 97.03%.

Experimental investigation on thermal-hydraulic performance of manifold microchannel with pin-fins for ultra-high heat flux cooling

The manifold microchannel (MMC) with pin-fins is fabricated and its thermal-hydraulic performance is experimentally investigated. The MMC with pin-fins is an embedded cooling device made of a manifold wafer and a microchannel wafer, anodically bonded to form a total thickness of 1 mm. A microchannel wafer has the etched micro pin-fins with a porosity of 0.75, fin diameter of ▪, and fin height of ▪. For comparison, MMC with plate-fins is also fabricated, in which the plate-fins have the same porosity, fin thickness, and fin height as the pin-fins. Experiments are performed using single-phase deionized water as the working fluid with flow rates ranging from 50 to 300 ml/min, corresponding to pumping powers ranging from 0.28 to 33 mW, which enables the dissipation of an effective heat flux up to 1.2 kW/cm2. The experimental results demonstrate that employing pin-fins improves the thermal-hydraulic performance of the MMC heat sinks compared to using the plate-fins: an average 40% reduction in the effective thermal resistance (the total thermal resistance subtracting the conduction resistance) at a fixed pumping power condition. This is attributed to the fact that the MMC with pin-fins exhibits 20% higher heat transfer coefficient and 40% greater effective heat transfer area, even with 25% lower pressure drop on average compared to the MMC with plate-fins. At the highest tested flow rate of 300 ml/min, the MMC with pin-fins successfully dissipates the heat flux of about 1.2 kW/cm2 without phase-change heat transfer while maintaining the heater temperature below ▪. This is achieved with only 7 mW of pumping power, corresponding to the COP of 41,300 – a 5.3-fold increase in the COP compared to the MMC with plate-fins under the identical heater temperature and the flow rate conditions. Therefore, this study suggests that the MMC with pin-fins is an energy-efficient cooling device for the thermal management of ultra-high heat flux electronics.

Topologically optimized manifold microchannel heat sink with extreme cooling performance for high heat flux cooling of electronics

The manifold microchannel heat sink (MMCHS) has become one of the most promising cooling solutions for high heat flux electronics due to its lower pressure drop and higher temperature uniformity compared to the traditional microchannel heat sink (MCHS). However, the microchannel configurations in previous MMCHS are dominated by parallel, straight microchannels, which would limit their further enhancement in cooling performance. In this work, we designed the microchannel configuration in the MMCHS using a topology optimization method and proposed a manifold microchannel heat sink with a topologically optimized microchannel substrate (MMCHS-TOMS). The thermohydraulic performance of the MMCHS-TOMS was experimentally and numerically studied. The results showed that the microchannel configuration with optimal cooling performance is achieved at a width ratio of inlet to outlet (Win/Wout) = 0.5 and inlet pressure (Pin) = 10 Pa. The MMCHS-TOMS demonstrates a uniform flow distribution in adjacent arrays, and the discrepancies of volumetric flow rate (V̇d) among all inlets are less than 6 %. The MMCHS-TOMS is capable of removing 1570 W/cm2 heat flux under a footprint area of 42 × 10.5 mm2 with a pressure drop of 11.9 kPa, in which the volumetric flow rate and inlet temperature are 3 L/min and 293 K, respectively. With a volumetric flow rate of 1 L/min and a heat flux of 687 W/cm2, the MMCHS-TOMS achieved a maximum cooling coefficient of performance (COP) of 78273, which is the highest value reported up to date. Moreover, oscillations in temperature (mild) and pressure drop (large) are observed in the MMCHS-TOMS when violent boiling occurs; the system stability caused by those oscillations can be suppressed via increasing the volumetric flow rate, although the COP would thus be reduced.