Liquid-cooled Heat Sink Research Articles

Parametric model and experimental investigation of a distribution header to relieve heat sink coolant maldistribution

Coolant maldistribution has obvious negative effects on the liquid cooled heat sink (LCHS) performance. This work proposed a distribution header parametric model to improve flow distribution and compared with conventional I-type LCHS. The distribution header was a symmetrical S-shaped structure with a drop-shaped baffle. The S-shaped outline was obtained through a streamlined design to reduce the flow resistance. The structure characteristics of the drop-shaped baffle, which first expands and then contracts, were conducive to change the flow direction and relieve flow maldistribution. The experimental and numerical results indicate that the S-shaped outline parameters exhibited small impact on fluid distribution improvement, but distinctly affected pressure drop. The parameters of the drop-shaped baffle had significant influence on the fluid distribution. Notably, compared with conventional I-type LCHS, the LCHS with distribution header can improve the heat transfer, fluid distribution and flow performance. The maximum temperature of the measuring points was significantly decreased by 12.12 %−14.62 %, pressure drop was reduced by 2.78 %–4.44 %, and the flow distribution was improved by 68.32 %. The conclusions proved that the distribution header is based on a simple design with lower energy consumption, and which can be used into LCHS to relieve the flow maldistribution.

On the design of manifolds for parallel channel systems

In the design of high-performance heat and mass transfer devices such as liquid-cooled heat sinks, catalytic reactors, and catalytic convertors, parallel mini/microchannels are favored owing to their special potentials. Offering low pressure drop, providing high transfer surface area to volume ratio, and being easy to manufacture and optimize have been drawing thermal and chemical engineers attention to parallel channels for past decades. When working with parallel channels, the challenge of flow maldistribution is commonly faced which decreases their efficiency significantly. System total pressure drop and flow uniformity are two parameters that determine the system performance. In the present study, a variety of practical ideas, aiming to enhance parallel channels performance, are studied numerically. Inventive manifold designs with high hydraulic performance are created through the course of this study. The results of these designs are compared with basic conventional designs which show substantial enhancement. Analyzing less successful designs lead us to deep understanding of fluid dynamics in parallel channel heat and mass transfer devices.

Multi-objective topology optimization design of silicon carbide metal oxide semiconductor field effect transistors power module liquid-cooled heatsink for electric vehicles

Silicon carbide (SiC) metal oxide semiconductor field effect transistors (MOSFETs) is gradually replacing silicon-based insulated gate bipolar transistor (IGBT) as the switching devices in electric vehicle power inverters due to its higher operating temperatures, switching speeds, and frequencyies. However, the high switching frequency of SiC MOSFETs can increase the losses of the power inverter, resulting in an increase in the temperature, which will limit the performance of power inverters. The improvement of power module performance is mainly controlled by optimizing its control methods during operation and improving its cooling system. Currently, the liquid-cooled heatsink used in power modules have disadvantages such as large flow resistance and poor heat dissipation performance. In order to enhance the performance of the heatsink, this study first established a three-dimensional finite element model of SiC MOSFETs power module based on a pin fin heatsink. The accuracy of the model was verified by numerical and experimental methods. Secondly, based on numerical analysis, a multi-objective topology optimization method for the power module liquid-cooled heatsink is proposed. This method takes heat exchange and fluid dissipation energy as the objective function and uses weight factors to adjust the influence of each on the objective functions. Additionally, the temperature distribution of the heatsink is considered to optimize its performance. Finally, the numerical results show that the topology-optimized heatsink exhibits better performance at high coolant volumetric flow rates. When the coolant volumetric flow rate is 14 L/min, the pressure drops of topology-optimized heatsink is reduced by 63.94 % and the junction temperature of the power module is reduced by 0.24 % compared with the pin fin heatsink. This topologically optimized heatsink could be helpful to improve the performance of existing power module heatsinks.

Optimized design and simulation study of liquid-cooled heat sink model for IGBT module based on TPMS structure

Abstract In this paper, we propose a liquid-cooled heat sink model utilizing a TPMS (triple periodic minimal surface) structure for IGBT modules. Using parametric modeling software nTopology, we establish three TPMS structures: Schwarz P, Gyroid, and Diamond. Thermal simulation analysis is conducted on the radiator model using ANSYS Fluent. The optimal structural parameters are determined to ensure effective heat dissipation while preventing excessive pump power consumption due to inappropriate inlet flow rates. Simulation results demonstrate that the liquid-cooled radiator with TPMS structure outperforms conventional radiators in heat transfer efficiency, albeit with higher inlet and outlet pressure drops. Among the TPMS-structured radiators, the Schwarz P configuration exhibits the lowest pressure drop, approximately 20% less than the remaining two, offering superior thermal management advantages.

Maximizing liquid-cooled heat sink efficiency with advanced topology-optimized fin designs

Direct-to-chip liquid cooling offers significant advantages in managing higher power densities compared to traditional air-cooling methods. This approach utilizes nearly half the power required by server fans and air conditioners, enhances cooling efficiency in data centers. The effectiveness of this cooling strategy is intricately linked to the layout of the cold plate fins. In this research, a density-based topology optimization method is implemented in generating free-forming and non-intuitive fin structures. A pseudo-optimization model, which approximates the 3D heat sink as two 2D thermally coupled problem is selected and optimized with ‘pressure drop’ and ‘average junction temperature’ as objective function and constraint, respectively. Several fin layouts with inlet flow velocities and temperature constraints are generated. Three-dimensional numerical simulations reveal that the average junction temperature with the topology-optimized fin pattern is ∼2°C higher, and the pressure drop is significantly lower compared to size-optimized straight channel. Building on this, an inverted topology-optimized design is introduced along the channel length, inspired by the wavy nature of sectional fins. The average junction temperature with the inverted TO design is 3 to 4°C lower compared to the straight design, with a similar pumping power of 0.023 W. The TO fin layout capitalizes on frequent re-initialization of boundary layers, secondary flow-induced mixing, and the formation of Dean vortices along the channel length. Further refinement leads to the derivation of drop-oblique-trapezoidal and oval-shaped (DOTO) fins. These fins reduce average junction and wall temperatures by ∼23% compared to the inverted TO design, owing to the persistent effects of fluid dynamic phenomena along the channel length. Comparison with benchmarked designs indicates that DOTO fins reduce the average junction temperature by 3 to 6°C compared to size-optimized offset strip fins and step fins, with a similar pumping power of 0.083 W. The study indicates that optimizing DOTO fins dimensions can further enhance heat sink performance.

Design and Optimization of Accumulator Pack

For an electric scooter, a lithium-ion battery with a Acro Butyl-nitrate (ABS) temperature management system was developed. Without the use of active cooling components like a fan, a blower, or a pump used in air/liquid-cooling systems, passive thermal management systems employing ABS can regulate the temperature excursions and maintain temperature uniformity in Li-ion batteries. Therefore, this new type of thermal management system can provide the benefits of a small, light, and energy-efficient system. The simulation results for a Li-ion battery sub-module with twenty 18650 Li-ion cells encased in ABS and a melting point of 114 to 120 °C are displayed. There are many important advantages to using aluminium fins manufactured from 0.7mm thick aluminium sheet between the battery cells in an accumulator pack. The relevance of them is explained in the following ways: Accumulator packs, particularly those used in high-power applications like scooters, can produce large amount of heat when in use. The performance, longevity, and safety of battery cells are all significantly impacted by heat. Aluminium fins serve as heat sinks and enhance heat dissipation by boosting the amount of heat-transfer surface area. Heat can be effectively transferred from the cells to the fins thanks to the thin aluminium sheet. Temperature Control: Battery cell efficiency and longevity depend on maintaining their temperature within a favorable range. By releasing more heat, aluminium fins assist in controlling the temperature. The fins aid in preventing overheating and preserving a more constant operating temperature by efficiently draining heat from the cells. Thermal Uniformity: The accumulator pack's thermal uniformity is enhanced by the inclusion of aluminium fins between the battery cells. Variations in cell temperature can cause performance imbalances and lower pack efficiency because uneven heat distribution can cause temperature differences among the cells. The fins aid in the even distribution of heat throughout the cells, reducing temperature variations and fostering consistent performance. Reduced Hotspots: Hotspots are small, high-temperature regions inside a battery pack that can hasten degradation and pose safety issues. Aluminium fins aid in heat dissipation, which reduces the development of hotspots. The fins' increased surface area enables more effective heat transport, which lowers the possibility of localized temperature accumulation. Improved Safety: Effective heat dissipation with aluminium fins can aid in accumulator packs' increased safety. Battery cells may experience thermal runaway or other dangerous situations as a result of high temperatures. The risk of thermal incidents is decreased by maintaining lower cell temperatures, improving operational safety in general. It's crucial to remember that parameters like spacing, size, and overall pack should be taken into account while designing and using aluminium fins. Additionally, by lowering the amount of heat that is released into the environment, liquid cooled heatsinks can be utilised to lessen the environmental effect of electronic equipment. The following are some benefits of employing liquid-cooled heatsinks: ● more efficient at cooling than heatsinks that use air cooling ● can be used to enhance the functionality and dependability of electronic equipment ● can be used to lessen how harmful electrical devices are to the environment. The following are some drawbacks of employing liquid-cooled heatsinks: ● more expensive than heatsinks that are air-cooled. ● more difficult to install and keep up ● Tend to leak more frequently. Keywords — CFD, 18650,ABS ,ALUMINUM FINS ,DRIVE CYCLE MODELS,EQUIVALENT CIRCUIT MODEL.

Performance enhancement of topology-optimized liquid-cooled heat sink with increased spanwise length of design domain

Topology optimization generate promising ‘heat sink fin layouts’ to satisfy the thermo-hydraulic objectives with lightweight designs. This article evaluates the performance of topology-optimized liquid-cooled heat sinks with different spanwise length-based design domains. A reduced-scale model (with 1/8th the width of the full-scale heat sink model) is selected and optimized with ‘pressure drop’ and ‘average junction temperature’ as objective functions and constraints, respectively. Fin layouts consisting of non-continuous fins are derived for different inlet flow velocities and temperature constraints using an accurate two-dimensional (2D) mathematical model, mimicking a three-dimensional (3D) heat sink geometry. Three-dimensional CFD simulation is used to compare the performance of the present fin layout with a reference topology-optimized design (with 1/16th the width of the full-scale model) and an augmented straight channel-based heat sink. To cool the heat sink to an average junction temperature of 50 °C, the present design requires 17 % and 54 % lower pumping power compared to the reference design and straight channel with significantly reduced material volume. Flow phenomena such as secondary flow-induced mixing and frequent reinitialization of boundary layers at leading edges of fins are observed during numerical investigation which are illustrated using velocity and temperature contours. The optimized fin layout's overall performance is compared with existing fin designs of heat sinks such as step fins, offset strip fins, oblique fins, and oblique and trapezoidal fins. Oblique and trapezoidal fin and oblique fin compete with topology optimized design which outperforms at lower flow rates (for velocity ranging from 0.05 m/s to 0.175 m/s). The average junction temperature using Oblique and trapezoidal fins and oblique fins are 63 °C and 61.22 °C, respectively compared to 58.5 °C for topology-optimized design with a similar pressure drop of 300 Pa.

Liquid-cooled heat sink design methodology with technical and commercial viability considerations: Case study of a partially 3-D printed prototype

A two-step methodology is proposed for the design and optimization of liquid-cooled heat sinks, where manufacturing costs are included as a commercial viability assessment metric. First, manifold modifications were made to reduce pressure losses in the baseline design. Second, a full-factorial parametric computational fluid dynamics (CFD) study fed an artificial neural network (ANN) model for further optimization. The aforementioned methodology was applied to the optimization of liquid-cooled heat sinks for CPU cooling. The baseline design consisted of a 3-D printed resin plenum mounted on a metallic heat spreader with parallel fin channels. The plenum delivers a slot jet along the center of the heat sink into a central passage that bifurcates the fin channels. An improved plenum design with ∼11% lower pressure losses than the baseline model was generated after the first optimization step. The designs generated in the parametric CFD study achieved average thermal resistances as low as 0.01 K/W for a theoretical pumping power range of 50–350 mW. A representative design from this study was manufactured and experimentally tested to assess the simulation approach, providing reasonable agreement with the numerical results. Consecutively, the ANN allowed for a higher resolution sampling of the design space, where optimal configurations were found in terms of an overall thermo-hydraulic performance parameter and an additional metric accounting for manufacturing costs. The methodology reported herein caters to heat sink designers seeking commercialization of their prototypes as the contrast between technical performance and manufacturing costs is addressed. Additionally, the mathematical tools utilized allow for cost-effective topology optimizations.

Interfacial characteristics in multi-material laser powder bed fusion of CuZr/316L stainless steel

This research investigates the multi-material laser powder bed fusion (MM-LPBF) printing of CuZr/316 L stainless steel (SS) within the same layer using four printing strategies. Printing CuZr first exhibits better quality. Conversely, printing 316 L SS first led to notable cracks due to elevated thermal stress and resulted in a larger diffusion zone due to material convection caused by the Marangoni effect. Material overlapping is effective in reducing the formation of cracks and creating a larger diffusion zone compared to non-overlapping. A topology-optimized liquid cooling heat sink with CuZr core and 316 L SS protective layer was printed to demonstrate electronic cooling applications.

Suitability of Embedded Liquid Cooling and Heat Generation for Chips.

Embedded liquid cooling is a preferred solution for dissipating the heat generated by high-power chips. The cooling capacity and pump power consumption of embedded liquid cooling heat sinks differ significantly between different structures. To achieve an accurate match between cooling capacity and heat dissipation requirements, the selection of a liquid-cooled heat sink should be carefully considered in conjunction with the heat dissipation needs of heat sources in real-world thermal management issues. Based on the manufacturing limitations on chip temperature and microchannel pressure, a composite performance index function was developed to assess the cooling capacity and cooling cost of the heat sink. This allowed for the establishment of an evaluation standard to determine the suitability of embedded liquid cooling and heat sink for the heat source. In this study, the suitability of four microchannel heat sinks with the same feature length and fin volume was evaluated under various thermal load conditions. The results show that the best-suited heat sink changes with variations in the thermal load of the chip. In the example, when the heat source was homogeneous at 100 W, the circular section pin fins have an optimal suitability of 0.928 for Re = 500. When the heat source was a heterogeneous heat source with a power of 100 W, the value of Θ was found to be 0.389. Additionally, the optimal suitability of drop section pin fins for Re = 971.5 was determined to be 0.862.

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

Experimental study on the thermal performance of a liquid-cooled heat sink integrating heat pipes for dual CPU servers

The increasing power consumption of server CPUs poses a challenge for data center cooling. In this work, a liquid-cooled heat pipe heat sink (LHPHS) with compactly arranged heat pipes is designed and fabricated for CPU cooling in dual CPU servers. Water is selected as the working fluid in the heat pipes. Experiments are conducted to explore the heat dissipation potential of LHPHS under high inlet coolant temperature and high heat load conditions, and to investigate the operational stability of LHPHS under the conditions of uneven heat generation between two CPUs. Furthermore, a one-dimensional thermal resistance network and numerical model of the LHPHS are established to quantitatively analyze the thermal resistance distribution of LHPHS and the variation of thermal resistance with coolant flow rate. The results show that, firstly, the LHPHS operates stably under high inlet coolant temperature and high heat load conditions, meeting the heat dissipation requirements of up to 37.5 W/cm2 with a coolant flow rate of 1 L/min and inlet coolant temperature of 35℃. Secondly, the LHPHS exhibits excellent performance in controlling temperature difference between CPUs and even when there is discrepant heat generation between them. Thirdly, the LHPHS performs a low thermal resistance, measuring 0.044 ℃/W at a coolant flow rate of 0.5 L/min, and this resistance further decreases as the flow rate increases. Additionally, it is observed that the thermal resistance of the liquid-cooled plate decreases with the increasing flow rate, and heat transfer within the heat pipes becomes a critical aspect under high coolant flow rates. Therefore, reducing the thermal resistance of the heat pipe is crucial for the thermal performance improvement of the LHPHS.

Investigating the performance of conventional and hydrophobic surface heat sink in managing thermal challenges of high heat generating components

In the pursuit of optimizing heat dissipation and improving performance in electronic devices, liquid-cooled heat sinks have garnered significant interest due to their potential to improve heat transfer efficiency. Presented study set out to assess the effectiveness of straight channel heat sinks as a thermal solution for high heat generating electronics components, while also investigating the impact of applying a hydrophobic coating on their performance. A series of tests were conducted at different heating powers (50W-250 W) and flow rates (200–950 ml/min), while also considering different orientations and directions of flow. The investigation focused on analysing critical aspects such as heat transfer performance, wall temperature variations, thermal resistance, and pressure drop characteristics of straight channel heat sinks with conventional and hydrophobic-coated surfaces. The results showed that the Nusselt number increased with higher Reynolds numbers and heating powers, indicating improved heat transfer efficiency. However, the hydrophobic coating on the heat sink surface led to a reduction in the Nusselt number due to the formation and retention of bubbles, hindering heat transfer. The maximum average reduction of 20.85% in Nusselt number was noticed at 100 W for the vertically positioned hydrophobic-coated heat sink with downward flow compared to conventional surface (CS) heat sink. Additionally, the findings revealed that pressure drop is influenced by Reynolds number and the presence of bubbles, with gravity playing a role in reducing pressure drop in certain orientations. A hydrophobic coating shows a small decrease in pressure drop, but bubble formation limits its effectiveness to some extent. Comparisons also indicated that the highest average decrease in pressure drop about 11.92% was observed for the same configuration, vertically positioned hydrophobic heat sink with downward flow, at 50 W. Moreover, the study's findings have broader implications beyond electronics. Heat sinks are widely employed in various industries, including automotive, aerospace, renewable energy systems, and industrial processes.

Performance Evaluation and Optimization of Series Flow Channel Water-Cooled Plate for IGBT Modules

The stability in the operation of insulated gate bipolar transistor (IGBT) modules plays a crucial role in wind power generation. It is essential to improve the thermal performance of the heat sink of IGBT modules in wind power converters and reduce the power consumption of liquid cooling systems, in order to optimize the heat dissipation of IGBT modules in wind power converters. In this paper, a simulation model of the liquid-cooled heat sink of the IGBT module is established and the performance of three different series flow channel structures is compared by computational fluid dynamics (CFD). Moreover, based on the orthogonal test design, the three factors (channel width, channel height, and cold plate wall thickness) affecting the performance of the water-cooled plate were ranked and optimized. The results show that the water-cooled plate with double-helical-type flow channel structure has the best comprehensive performance. In addition, for the double-helical-type structure, the optimal combination of channel structure parameters about channel width, channel height, and cold plate wall thickness is obtained. After optimization, the maximum IGBT temperature, thermal resistance, and pressure drop of the cold plate are reduced by 3.13%, 5.78%, and 18.87%, respectively, compared with the double-S structure in parameter case one. The proposed methods and results are expected to provide theoretical guidance for the thermal management of IGBT modules in wind power converters.

CFD Analysis of Liquid-Cooled Heatsink Using Nanofluids in Computer Processors

CFD Analysis of Liquid-Cooled Heatsink Using Nanofluids in Computer Processors

Topologically optimized mini-channel heat sinks for reduced temperature non-uniformity

Water-cooled mini-channel heat sinks are widely used for thermal management of electronic devices, but their flow paths are usually limited to simple designs, such as parallel channels, due to manufacturing limitations. Such designs do not distribute flow uniformly, resulting in non-uniform heat transfer across the heat sink and significant temperature gradients. A liquid-cooled heat sink with a millimeter high flow channel was designed and fabricated to cool an 86 mm x 63 mm uniformly distributed heat load. A density-based topology optimization model was implemented in COMSOL to generate a non-traditional internal geometry that minimizes temperature non-uniformity. The topologically optimized heat sink was made using a novel thermal spray additive manufacturing method in which molten aluminum was sprayed into a cavity machined in an aluminum plate through a polymer mask made in the shape of the desired flow channels by 3D printing. The cavity was closed with an aluminum plate to create a sealed heat sink. The thermal performance of the topologically optimized heat sink was compared experimentally to that of a heat sink with parallel channels. Each heat sink was placed on a uniformly heated copper block dissipating 180 – 630 W (corresponding to heat fluxes of 3.3 – 11.6 W/cm2) and its temperature measured by an array of 9 thermocouples embedded in the heated heat sink face while water flowed through it at rates of 100–1500 mL/min. The optimized heat sink maintained lower surface temperatures and reduced temperature non-uniformity on its surface at all flow rates tested. Numerical simulations demonstrated that this was due to better flow distribution by the topologically optimized flow channels.

Review on PCM Heat Sink for Electronic Thermal Management Application

A significant challenge in thermal management has arisen as a result of the rising demand for high-performance electronic devices. The efficiency, size, and weight of conventional cooling methods like liquid and air cooling are constrained. Due to their high storage of latent heat capacity and isothermal phase transition behavior, phase change materials (PCMs) have become a promising thermal management solution. The purpose of this experimental study is to evaluate the performance of a PCM heat sink for electronic thermal regulation. The PCM heat sink is made up of a PCM module attached to a typical heat sink. To improve heat dissipation capabilities, the PCM module uses a PCM material with a suitable phase change temperature and encapsulation. The experimental setup involves simulating real-world operating conditions by applying controlled heat loads to electronic components. By observing temperature changes, thermal resistance, and transient response, the PCM heat sink’s thermal performance is assessed. To evaluate the superiority of the PCM heat sink, a comparison is made with traditional air-cooled and liquid-cooled heat sink configurations. The experimental investigation’s findings show that the PCM heat sink performs better in terms of thermal management than traditional cooling techniques. The phase change process used by the PCM efficiently absorbs and stores extra heat produced by electronic parts, improving temperature regulation and lowering temperature gradients. Lower component temperatures and higher operational reliability are the results of the PCM heat sink’s improved thermal resistance and heat dissipation efficiency. A further benefit of the PCM heat sink’s isothermal behavior during the phase transition is that it prevents temperature spikes and lessens the effects of heat stress on the electronic devices. The long cooling times provided by the PCM material’s high latent heat storage capacity allow for prolonged operation without affecting device performance. This experimental study concludes by demonstrating the efficiency of a PCM heat sink for electronic thermal management. The design of heat sinks with PCM integration offers notable enhancements in temperature control, thermal resistance, and system overall reliability. The results of this research help to advance thermal management strategies, which makes it easier to create efficient electronic devices with better cooling capacities.

A Highly Integrated Multichip SiC MOSFET Power Module With Optimized Electrical and Thermal Performances

This paper proposes a highly integrated multichip silicon carbide (SiC) MOSFET power module packaging with optimized electrical and thermal performances. The structure of the module is to stack the two power switches up and down with the cooling system and the decoupling circuit integrated inside the module. The structural characteristics of the module realize the co-optimization of the switching performance, thermal management, and electromagnetic interference (EMI) issue of the multichip SiC module, which effectively solve the contradiction in the optimization of the electrical and thermal performance. In addition, by optimizing the process flow and designing a variety of soldering fixtures, the feasibility of the process and the engineering margin is increased. Experiments and simulations show that the proposed SiC power module has good electrical and thermal performance. The loop parasitic inductance is reduced to 2.02 nH and the common-mode (CM) current is eliminated. The drain–source voltage overshoot during the turn-off transient is reduced by 76.5%, and the voltage oscillation is significantly improved due to the integration of the decoupling circuit. At the same time, the integrated liquid-cooling heatsink greatly improves the cooling efficiency of the module on the premise of ensuring the insulation performance of the module.

Thermal analysis of Si-IGBT based power electronic modules in 50kW traction inverter application

Estimation of accurate IGBT junction temperature is crucial for reliability assessment. The well-known RC lumped approach can help predict junction temperature. However, this method suffers from inaccuracy while characterizing the thermal behaviour of several IGBT modules mounted to the liquid-cooled heatsink. Specifically, the thermal challenge originates from the thermal cross-coupling and module-to-module heat spreading and the converter cooling condition. This article demonstrates a methodology to study the impact of heat spreading, thermal interface material, and massive size liquid cold-plate on the overall thermal behaviour. A case study of 50 kW traction inverter is chosen to demonstrate the benefit of early assessment of electro-thermal simulation before making costly prototype design. Power loss is initially estimated using an analytical loss model and later the estimated power loss is used in FEA (Finite Element Analysis) thermal model. This paper also compares the performance of single-phase and two-phase liquid cooling and various thermal interface materials (TIM) to determine which type of cooling system and TIM is most suitable for real applications. Simulation results suggest that combination of two-phase liquid cooling and TIM can improve the thermal performance and reduce junction temperature by 4.5%, 4.2%, 4.6% for the traction power load 30 kW, 40 kW, and 50 kW, respectively. The proposed methodology can be used as useful reference guidance for thermal design and modelling of IGBT based power converter applications.

Conventional and topologically optimized polymer manifolds for direct cooling of power electronics

Single-phase liquid-cooled heat sinks are a preferred mode of thermal management for many power dense electronic applications. This paper studies the design, optimization, and thermal-hydraulic performance of polymer manifolds directing coolant to the base plate of multi-chip power modules. Direct cooling eliminates the need for thermal interface materials which form a major bottleneck to junction-to-coolant thermal resistance reduction in state-of-the-art metallic cold plates. We use 2D topology optimization (TO) to develop designs using side view (SVTO) and top view (TVTO) sections of the flow domain in contact with the power module base plate. We also use 3D TO design (CTO) which combines SCTO and TVTO. The TO designs are compared against conventional mini-channel designs including rectangular, zig-zag and serpentine channels. Cooling performance of the different designs is computed using computational fluid dynamic (CFD) simulations. Experimental quantification is achieved through measurements of the silicon carbide device junction temperature and inter-device temperature difference along with the pressure drop influencing the pumping power requirement. The CFD simulations were used to identify optimized manifold designs which were fabricated using selective laser sintering of PA12 and validated experimentally using surrogate heaters. Zig-zag designs showed the best performance among the conventional designs (0.93 (cm2·K)/W), at the cost of high pressure drop (> 2.4 kPa). Serpentine channel designs were effective in limiting inter-device temperature difference (< 0.26⁰C) through multiple changes of flow direction. The TO designs improved the performance (1.1 (cm2·K)/W) when compared against conventional channels showing lower maximum temperatures with lower pressure drops (0.8 kPa). Fluid manifolds are shown to greatly influence the coolant flow field, leading to flow maldistribution with low velocity pockets, emphasizing the need for optimizing the complete manifold design.