Liquid-cooled Heat Sink Research Articles

Liquid-cooled heat sink design for a multilevel inverter switch with considerations for heat spreading and manufacturability

Multilevel inverter switches (MIS) present a thermal management challenge by virtue of their small size yet high power operation. In this contribution, a water-cooled heat sink for an MIS was designed and optimized through a series of computational fluid dynamics simulations and surrogate modeling. The parameters under consideration were technical metrics (thermal resistance, pressure loss, and temperature uniformity) and manufacturing costs. The stark difference between air-cooled and liquid-cooled heat sinks was demonstrated in parallel modeling efforts. The heat sink consisted of a metallic baseplate with pin-fins and a separate resin manifold containing an array of nozzles for flow impingement and fluid extraction. The pin–fin baseplate was parametrically designed using three different fin densities: restricted array (RA), variable array semifull (VAS), and variable array (VA), where fin diameter and pitch were correlated. The manufacturability of each design iteration was determined by obtaining quotes from a vendor. Since all heat sinks had the same inlet manifold, the pressure drop was similar across heat sink designs, indicating that the fin distribution had a minimum effect on the overall pumping power required for circulating the flow through the heat sinks. Effective thermal resistance calculations illustrated a complex interplay between fin diameter and pitch spacing. The complexity was better visualized using a feedforward neural network (FNN) and an overall performance metric (PPTR). A sensibility analysis using the FNN indicated that the fin pitch was the dominant variable in the determination of the overall heat sink performance. The PPTR allowed the creation of a ranking system that matched the FFN outcome and indicated that the VA2D1 design was the most technically promising; nonetheless, once manufacturing cost was considered in the analysis, as PPTR-$, the RA1D1 was the most commercially viable as it satisfied technical cooling goals per the lowest unit cost.

Influence of secondary flow angle and pin fin on hydro-thermal evaluation of double outlet serpentine mini-channel heat sink

Achieving high processing speed in electronic components combined with large amount of generated heat, this heat removed by heat sink. For extreme heat generated, a mini-channel liquid cooled heat sink is used. The aims of the present study are to enhance the efficiency of the serpentine mini-channel heat sink and to uniformly temperature distribute. To achieve that, several variables were studied, namely the double outlet, the secondary flow channel with different backwards angles (45°, 53°, 61°) and finally the combination of secondary flow with pin fin at different pitch distances (5d, 6d, 7d). Ansys Fluent 2020 R2 software was utilized to extract the numerical results. The two models were fabricated and tested experimentally, namely the Basic model and the optimum model (model F), to validate the numerical results. The results of validation showed a good agreement. The results show that the use of a double outlet serpentine mini channel heat sink leads to an increase in overall performance to 1.47 and a lower maximum base temperature. With an 8.7% increase in overall performance and an even lower base temperature, the secondary flow backward angle of 53° (model C) outperforms the other two angles. However, combining the secondary flow with the pin fin enhances the heat sink both thermally and hydraulically. The model F displays the maximum performance with a 1.79 and a Nusselt number of 9.64% as compared to the Basic model.

Technical and commercial viability assessment of liquid-cooled heat sinks for a circuit board with discrete heat loads

In this contribution, existing gaps in the design process of liquid-cooled heat sinks, i.e., the lack of overall performance assessment metrics and commercial viability analyses, are addressed. This work focused on the design of a cost-effective cooling system for a commercial circuit board with multiple and asymmetric heat sources designed and manufactured by an electronics company. The analysis was performed using 3-D computational fluid dynamics simulations across sixteen different cases, focusing on the effect on performance and manufacturing cost of two primary design features of liquid-cooled heat sinks: the inlet and outlet manifolds and heat transfer enhancing features, where pin fins and minichannels were considered. Specifically, the effect of diameter and spacing of the pin fins and the effect of the distribution and length of the mini channels over an unevenly heated surface were parametrically investigated. The tradeoff between thermal and hydraulic performance of the heat sinks was reconciled using an overall performance parameter, which allowed for a single numerical evaluation of the heat sinks’ global performance spanning several operating flow conditions. Likewise, the tradeoff between cost and performance was investigated by comparing the manufacturing cost of the different heat sink designs, including two heat spreader materials. Lastly, a comprehensive assessment of the potential cooling solutions for the circuit board was done by combining the overall performance and manufacturing cost per prototype through a novel parameter proposed herein. The broader liquid-cooled heat sink design approach reported in this work is a missing aspect in similar contributions, as the focus is solely on technical performance parameters, while commercial implementation issues (manufacturability and production cost) are neglected.

Liquid Cooled Microchannel Heat Sink Based Peltier Solar Atmospheric Water Generator

To maintain the high RH value near dry air vent, increase the efficiency of Peltier with proper ventilation that is to make the heat escape easily, to provide more surface area for heat sink to cool down the air more effectively. Mass of the body is reduced, and durability is improved. RH value is maintained with the help of dry air vent. We can get benefits from a liquid cooled micro channeled heat sink which needs only a little space. It is suitable for the high flux heat dissipation and also gives a better result compared to generic convection method. It is used without reacting with the body frame. It is portable with help of 12V DC solar 10W. This system solves water scarcity in rural areas. We can especially use at hill stations as the humid conditions are the best.

Novel design of a liquid-cooled heat sink for a high-performance processor based on constructal theory: A numerical and experimental approach

This study presented a novel liquid-cooled heat sink based on constructal theory. An experiment was conducted to investigate the influence of boundary conditions, such as the mass flow rate (ṁ), on heat transfer rate (Qin) and pressure drop. Five cylinder heater cartridges were used in the experiment for 11 different mass flow rates (0.008292 <ṁ (kg/s) < 0.03307).Through numerical simulation, the effects of changing the number of clusters on heat transfer and pressure drop were studied. The results showed that the optimal combination of pressure drop and Nusselt number occurs in four clusters. According to the results, increasing the number of clusters can increase the Nusselt number by up to 11.98% and 13.62% for the highest (ṁ = 0.03307 kg/s) and lowest (ṁ = 0.008292 kg/s) mass flow rates, respectively. This work may lay the foundation for creating the next generation of thermal management systems for compact heat sources, such as the CPU in a self-driving car, robots and high-performance computers (HPC).

Design and test of shape memory alloy fins for self-adaptive liquid cooling device

• Self-adaptive cooling fins based on Shape Memory Alloys (SMA). • The set of conditions for proper operation are defined analytically. • The impact of an array of SMA fins on thermal resistance is experimentally studied. • Nearly constant wall temperature is achieved for varying heat flux scenarios. Thermal management complexity increases in high-performance chips, where the heat loads vary spatially and temporally, while liquid cooling systems are usually designed for most stringent stationary conditions. Several works developed heat transfer enhancement techniques to increase the cooling capacity of liquid cooled heat sinks, but pumping power is increased in a permanent way due to the addition of elements within the channels. Here, a liquid cooling self-adaptive heat sink that can efficiently adapt the distribution of its heat extraction capacity to time dependent and non-uniform heat load scenarios is proposed. Numerical design of the mesoscale cooling device with bimorph metal/SMA fins, definition of the fabrication and training procedure of the SMA fins to reach the desired behavior and experimental assessment is presented. The capacity of the self-adaptive fins to locally boost the heat transfer is numerically and experimentally demonstrated. Results obtained show that the self-adaptive fins can improve the temperature uniformity by 63% with respect to plain channel. The reduction in thermal resistance using bimorph metal/SMA fins sample allows the surface maximum temperature gradient to remain almost constant although heat flux increases. Energy savings are maximized in applications where partial load intervals contributes significantly to the overall operating period.

A synergic topology optimization approach on distribution of cooling channels and diverse-intensity heat sources for liquid-cooled heat sink

A synergic topology optimization approach on distribution of cooling channels and diverse-intensity heat sources for liquid-cooled heat sink

Experimental study on the performance of a tree-shaped mini-channel liquid cooling heat sink

Characteristic of high heat dissipation of semiconductor electronic products require the cooling systems operating throughout the year, which inevitably causes a huge energy consumption. Although the small-scale channel (i.e., mini-channel or microchannel) liquid cooling heat sink has been applied in semiconductor electronic products cooling accounting for its advantages of outstanding heat exchange performance and easy integration, the existing small-scale channel liquid cooling heat sink still has problems of uneven temperature distribution and excessive pressure loss. In this paper, a Tree-shaped mini-channel liquid cooling heat sink (TSMLCHS) with four levels branches is proposed. The models for determining the dimension of each branch are established. The effect of flowrates on the heat transfer efficiency and pressure loss for the proposed TSMLCHS is discussed in detail under different heat fluxes and flowrates. The experimental results show that the TSMLCHS is suitable for applying on the electronic chip cooling since the average surface temperature is only 23.8 °C–66.6 °C when the heat flux is varied from 5 W/cm2 to 8 W/cm2.

Cfd Simulation and Experimental Analysis of Cooling Performance for Thermoelectric Cooler with Liquid Cooling Heat Sink

Cfd Simulation and Experimental Analysis of Cooling Performance for Thermoelectric Cooler with Liquid Cooling Heat Sink

Multi-objective optimization of 3D printed liquid cooled heat sink with guide vanes for targeting hotspots in high heat flux electronics

The data center industry is currently faced with surging energy demands and a growing carbon footprint. Beside these, the industry is also faced with increasing chip power densities and thermal stresses, which can be attributed to the integration of multiple cores into a single chip. This paper presents a novel hot spot targeted cooling approach, the goal of which is to reduce both the cooling device's thermal resistance and chip thermal stresses while also lowering the pressure drop and pumping power required to cool the chip. The approach allows for the temperature of the liquid leaving the chip to be maximized, which can enable different heat recovery potentials. Multiple techniques were used to improve the heat sink's thermohydraulic performance, including a direct chip-attached heat sink, distributed water jet impingement inlets, and embedded guide vanes. A multi-objective optimization study was conducted to minimize the chip's temperature non-uniformity, thermal resistance, and pumping power. For optimization, a Bayesian-based learning technique was coupled with a genetic algorithm, which was then employed. The results show that the optimal design was comprised of variable fin density and profile in the hot spot and background regions of the chip. The optimized design showed a benchmark thermal resistance of 0.036 °C/W and a chip non-uniformity index as low as 0.81 °C. It outperforms the other hot spot targeted heat sinks that have been presented in previous literature, meanwhile also consuming relatively low pumping power.

Multiphysics Optimization of Thermal Management Designs for Power Electronics Employing Impingement Cooling and Stereolithographic Printing

Meeting the stringent performance requirements for power electronic converters in electric vehicles requires an integrated approach for optimizing the inherently coupled electrical and thermal performances of converter systems. This article presents a multidisciplinary thermal management design methodology that utilizes genetic algorithms (GAs) to generate topologically optimized geometries for liquid-cooled heat sinks. These GA-generated heat sinks are based on impingement cooling principles and leverage the flexibility of stereolithographic manufacturing techniques. The proposed optimization methodology incorporates the interdependence between the thermal and electrical aspects of the system, and it is capable of targeting performance metrics in either or both domains. This optimization process is demonstrated for a 6.6-kW integrated power module design employing bare-die silicon carbide devices on an FR4-based printed circuit board with embedded ceramic elements. Experimentally validated electrothermal multiphysics simulations of the GA-optimized heat sinks targeting various performance metrics show successful optimization of targeted metrics relative to the initial seed design. The results demonstrate the importance of the multidisciplinary design approach and the effectiveness of the GA-based optimization methodology.

Reduced Order Design Optimization of Liquid Cooled Heat Sinks

Abstract The recent growth in electronics power density has created a significant need for effective thermal management solutions. Liquid-cooled heat sinks or cold plates are typically used to achieve high volumetric power density cooling. A natural tradeoff exists between the thermal and hydraulic performance of a cold plate, creating an opportunity for design optimization. Current design optimization methods rely on computationally expensive and time consuming computational fluid dynamics (CFD) simulations. Here, we develop a rapid design optimization tool for liquid cooled heat sinks based on reduced-order models for the thermal-hydraulic behavior. Flow layout is expressed as a combination of simple building blocks on a divided coarse grid. The flow layout and geometrical parameters are incorporated to optimize designs that can effectively address heterogeneous cooling requirements within electronics packages. We demonstrate that the use of population-based searches for optimal layout selection, while not ensuring a global optimum solution, can provide optimal or near-optimal results for most of the test cases studied. The approach is shown to generate optimal designs within a timescale of 60–120 s. A case study based on cooling of a commercial silicon carbide (SiC) electronics power module is used to demonstrate the application of the developed tool and is shown to improve the performance as compared to an aggressive state-of-the-art single-phase liquid cooling solution by reducing the SiC junction-to-coolant thermal resistance by 25% for the same pressure drop.

Liquid-Cooled Heat Sink Optimization for Thermal Imbalance Mitigation in Wide-Bandgap Power Modules

Abstract Power semiconductor die placement on substrates used in high-power modules is generally optimized to minimize electrical parasitic (e.g., stray inductance, common-mode capacitance), taking into account the minimum spacing between semiconductor dies for thermal decoupling. The layout assumes sufficient heat spreading and transfer from dies to the cooling structure. Insulated metal substrate-based power module designs may lead to asymmetrical thermal resistance across the dies, which may cause significant temperature differences among the devices. Such unintentional thermal asymmetries can lead to oversizing the cooling system design or underusing the semiconductor power processing capability. This article proposes a thermal imbalance mitigation method that uses evolutionary optimized liquid-cooled heat sinks to improve the thermal loading among devices.

Design and optimization of a liquid cooled heat sink for a motor inverter in electric vehicles

The rapid development of power electronic devices has made them have higher power density, which puts forward higher requirements for cooling technology. The contribution of this paper is the integrated design of the liquid cooled heat sink for a 30 kW motor inverter considering the distribution of power devices. In order to find an optimal heat sink configuration, the cooling performance of three different configurations of heat sinks was investigated. And the distribution characteristics of the temperature and fluid velocity field were compared and analyzed. The heat sink with serpentine channel configuration was selected due to its best temperature uniformity and cooling characteristic. In addition, the effects of geometric parameters (fin thickness) and flow parameters (flow rate) on cooling performance were further studied. On this basis, the geometrical configuration of the heat sink was optimized. The experimental results of the optimized heat sink are in good agreement with the numerical simulation results. The motor inverter achieves high power density of 9.677 kW/kg.

A topology optimization based design of a liquid-cooled heat sink with cylindrical pin fins having varying pitch

An improved internal structure of a liquid-cooled heat sink has been proposed numerically and experimentally. The initial motivation is based on the results of thermal and fluid-flow topology optimization, which tends to produce a porous region despite suppression through the numerical scheme. The topology optimization was conducted using a Finite-Volume (FV) based procedure with a simplified sensitivity analysis as well as the globally convergent method of moving asymptotes (GCMMA) algorithm. The Spalart-Allmaras turbulence model was modified to handle the varying solid geometry in the topology optimization. As the result of multi-objective topology optimization showed a tendency towards the porous geometry inside the heat transfer domain, new models for the internal structure were proposed: a multi-layered porous medium with metal foam and varying-pitch cylindrical pin-fin structures. An experimental rig was developed for experimental validation of the proposed idea. The results shows that the varying-pitch cylindrical pin-fin structure inside the heat sink has advantages in heat transfer, pressure drop, and the manufacturability. Details of the numerical procedure and the experimental results are summarized in both quantitative and qualitative aspects.

Study of the performance of an integrated liquid cooling heat sink for high-power IGBTs

• An integrated heat sink was manufactured. • The performance of three common heat sinks were compared. • The cooling water temperatures have effect on the performance of the integrated heat sink. • The installation angles have effect on the performance of the integrated heat sink. To address the challenge of heat management for high-power IGBTs, a type of microchannel liquid cooling heat sinks integrated vapor chamber (VC integrated heat sink) was developed. Firstly, it compared with the VC separate heat sink and the simple microchannel heat sink under the same conditions. The experimental results showed that the VC integrated heat sink had less thermal resistance than the VC separated heat sink, and the relatively simple microchannel heat sink could significantly improve the temperature uniformity. The influence of the cooling water flow rate, temperature and inclination angle on the VC integrated heat sink was further studied. Reductions in the cooling water temperature led to decreases in the heat source temperature but did not improve temperature uniformity. The inclination angle had a significant influence on the performance of the VC integrated heat sink. The performance of the VC integrated heat sink was optimal when the inclination angle was 60°.

Design and research of cooling system for 2.5 MW permanent magnet wind turbine

In order to solve the problem of excessive temperature rise caused by 2.5 WM permanent magnet wind turbine in operation, this paper designs a heat dissipation system. The combination structure of the heat exchanger and the heat sink was determined, as well as the heat dissipation method of the internal and external cycle isolation heat exchange. The control method and operation mode with Siemens PLC as the core are put forward. The computational fluid dynamics method is utilized to design the air-cooling heat exchanger and the liquid-cooled heat sink of the heat dissipation system. The results show that the cooling pipe gap has a great impact on the liquid cooling effect. The cooling pipe arrangement and piping arrangement of the air-cooled heat exchanger and liquid-cooled radiator are optimized. Finally, taking a 2.5 MW direct-drive permanent magnet wind turbine as an example, four environmental temperatures were selected to test generators in rated power. Verify that the cooling system is designed to meet cooling requirements.

Study on the Performance of a Y-Shaped Liquid Cooling Heat Sink Based on Constructal Law for Electronic Chip Cooling

Abstract The power of one rack in a data center can be greater than 3 kW, which is released within a relatively small area. However, most of the heat in a data center is released from the electronic chips. Thus, the energy consumption of the air-conditioning system in a data center will be significantly decreased if the heat released by the electronic chips can be reduced directly. Although liquid cooling heat sinks (LCHS) have been demonstrated as an effective way to resolve this problem, the application of LCHS is limited by the uneven cooling distribution on the surface of the electronic chips and the liquid leakage of the LCHS. The constructal law optimizes the design of the pipeline by introducing the freedom of deformation in the fluid geometry to obtain the optimal global performance. In this study, a novel Y-shaped liquid cooling heat sink (YLCHS) was proposed based on the constructal law, in which the cooling water enters the center of the heat sink through the inlet pipe and diffuses into the periphery through the internal Y-shaped microchannels. A numerical simulation was carried out to determine the cooling effect of the YLCHS. Compared to those of the conventional S-shaped liquid cooling heat sink (CSLCHS), the peak surface temperature and the average surface temperature of the electronic chip with YLCHS were decreased by 15.2 °C and 6.3 °C, respectively. Furthermore, the pressure loss of the electronic chip with YLCHS was also reduced by 63.0%.

Performance Analysis and Shape Optimization of an Impingement Microchannel Cold Plate

Optimization of liquid-cooled heatsinks (cold plates) is of critical importance due to their widespread application in high-performance electronic packages consisting of heterogeneous integrated systems, field programmable gate arrays (FPGAs), and on-chip hotspots. In this study, the thermo-hydraulic performance of a commercial microchannel impingement cold plate is analyzed in detail. Impingement cold plates are preferred over parallel flow cold plates due to their lower pressure drop where there is no restriction on space (i.e., where flow can enter perpendicular to the electronic board). Splitting the flow into two branches cuts the flow rate and the path into half, which leads to a lower pressure drop through the channels. Since the fins of the present commercial cold plate (considered as the baseline design) are tilted, the effect of the fin tilt angle on the hydraulic and thermal performance of the cold plate is also studied. The response surface method (RSM) is used to optimize the geometry of the fins and impinging inlet. The results of optimization show that hydraulic resistance can be reduced by 50% without a remarkable change in thermal resistance. The effect of the geometric parameters on the cold plate thermo-hydraulic performance is studied using the computational fluid dynamics results at the RSM design points. The variation in the cold plate coefficient of performance with the coolant flow rate and inlet temperature is compared for the baseline design and a selected optimal design. Finally, the effect of impinging inlet geometry on the chip temperature profile is also examined.

Increasing the efficiency of a Peltier device by assessing the thermal performance of liquid-cooled microchannel heat sinks

Water is, arguably, Earth's most valuable and vital resource. Devices that extract water from the atmosphere have been intensely researched as a means of harvesting potable water in environments where it is otherwise scarce. One such device is a Thermoelectric Cooler (TEC); a device that utilises the Peltier effect to cool a system. TECs are a promising solution for atmospheric water generation (AWG) over their competitors due to their simplicity and refrigeration capabilities. Despite these advantages, TECs are still considered mostly inefficient as they demand relatively high costs and energy consumption. This meta-analysis focuses on optimising the efficiency of small-scale Peltier devices. It explores the means of optimising the liquid cooled heat sink by using a specific flow field microchannel configuration such that less pumping power is required to push the coolant and more energy can be saved. A combination of optimal operating current of the Peltier device and of a novel flow liquid-cooled microchannel heatsink configuration with bifurcated fins using Galinstan as a coolant promises a significant increase in water production per unit of energy consumption for the AWG system.