Search Results (123)

This study investigates the performance of lattice-structured heat sinks based on BCCz unit cells in comparison to conventional straight-fin and pin-fin designs. Various lattice configurations were explored. Numerical simulations and experimental evaluations were carried out to analyze thermal resistance, pressure drop, and temperature distribution under different operating conditions. Among the designs, the BCCz configuration with a circular cross-section was identified as the most promising candidate for integration into the final heat sink demonstrator, offering reliable and consistent performance. A prototype using the BCCz lattice structure was additively manufactured, alongside a conventional design for comparison. The results highlight the superior heat dissipation capabilities of lattice structures, achieving up to a 100% improvement in thermal performance at high flow rates and up to 300% at low flow rates compared to a conventional straight-fin heat sink. However, the pressure drop generated by the lattice structures remains a challenge that must be addressed. This work underscores the potential of optimized lattice-based heat exchangers to meet the severe thermal management requirements of railway power electronics. Full article

In recent years, the number of transistors on electronic chips has surpassed Moore’s law, resulting in overheating and energy consumption problems in data centers (DCs). Chip-level microchannel cooling is expected to address these challenges. Grooved heat sinks with droplet-shaped fins were introduced to modify the overall capability of the cooling system. The degree of impact of the distribution of grooves and fins was analyzed and optimized using the Taguchi method. Moreover, the coupling effect of flow and temperature fields was explained using the field synergy theory. The key findings are as follows: for thermal resistance, pump power, and overall efficiency, the influence degree is the number of combined units > number of fins in each unit > distribution of the combined units. The optimal configuration of 21 combined units arranged from dense to sparse with one fin in each unit achieves 14.05% lower thermal resistance and 8.5% higher overall efficiency than the initial heat sink. The optimal configuration of five combined units arranged from sparse to dense with one fin in each unit reduces the power energy consumption by 27.61%. After optimization, the synergy angle between the velocity vector and temperature gradient is reduced by 4.29% compared to the smooth heat sink. The coupling effect between flow and heat transport is strengthened. The optimized configuration can better balance heat dissipation and energy consumption, improve the comprehensive capability of cooling system, provide a feasible solution to solve the problems of local overheating and high energy consumption in DCs. Full article

The effects of fin height, base thickness, blackening, emissivity and thermal conductivity on the heat dissipation for die-cast aluminum alloy heat sinks were investigated comprehensively. The thermal conductivity and emissivity vary depending on the aluminum alloy. It was clarified whether correlations between the influences of these factors exist. Three aluminum alloys with different thermal conductivities and emissivities were used in this study. Four-finned heat sinks were produced by die casting. Four fin heights and three base thicknesses were tested. In the as-cast (non-blackened) heat sinks, the emissivity had a greater effect on the heat dissipation than the thermal conductivity did. In blackened heat sinks, the heat dissipation increased as the thermal conductivity increased. For both the as-cast and blackened heat sinks, the heat dissipation increased as both the fin height and base thickness increased. Correlations between these influencing factors were also investigated. The blackened heat sink made from aluminum alloy with larger thermal conductivity showed the best heat dissipation performance. Full article

In this study, the effects of different heat sink designs on the cold side of the modules in a thermoelectric generator (TEG) system placed between the compressor and the intercooler of a turbocharged tractor on the system performance were numerically analyzed. In the current literature, heat sinks used in TEG modules generally consist of plate fins. In this study, by using perforated and slotted fins, the thermal boundary layer behaviors were changed and there was an attempt to increase the heat transfer from the cold surface compared to plate fins. Thus, the performance of the TEG system was also increased. When looking at the literature, it is seen that there are studies which aim to increase the performance of TEG modules by changing the dimensions of p and n type semiconductors. However, there is no study aiming to increase the performance of TEG modules by making changes on the plate fins of the heat sinks used in these modules and thus increasing the heat transfer amount. In this respect, this study offers important results for the literature. According to the numerical analysis results, the total TEG output power, output voltage, and thermal efficiency obtained for S0.5H15 were 6.2%, about 3%, and about 5% higher than those for PF, respectively. In addition, the pressure drop values obtained for different heat sinks, except for aluminum foam, were approximately close to each other. In cases with TEG systems where different heat sinks were used, the intercooler inlet air temperatures decreased by approximately 3.4–3.5% compared to the case without the TEG system. This indicates that the use of TEG will positively affect the improvement in engine efficiency. Full article

Thermoelectric generator (TEG) has emerged as a critical technology for automotive exhaust energy recovery, yet there is still a lack of reviews analyzing automotive TEG structure design and optimization methods simultaneously. Therefore, this review consolidates structure design and methods for improving thermoelectric conversion efficiency, focusing on three core components: thermoelectric module (TEM), heat exchanger (HEX), and heat sink (HSK). For TEM, research and development efforts have primarily centered on material innovation and structural optimization, with segmented, non-segmented, and multi-stage configurations emerging as the three primary structural types. HEX development spans external geometries, including plate, polygonal, and annular designs, and internal enhancements such as fin, heat pipe, metal foam, and baffle to augment heat transfer. HSK leverages active, passive, or hybrid cooling systems, with water-cooling designs prevalent in automotive TEG for cold-side thermal management. Optimization methods encompass theoretical analysis, numerical simulation, experimental testing, and hybrid methods, with strategies devised to balance computational efficiency and accuracy based on system complexity and resource availability. This review provides a systematic framework to guide the design and optimization of automotive TEG. Full article

Efficient cooling is necessary for the reliability of phased-array radars for a longer life. With the miniaturization and functionalization of microchips, heat flux generated by these chips also rises sharply. Existing liquid cooling techniques are inadequate to meet the ever-increasing cooling requirements. The present paper examines the potential to enhance the convective heat transfer of minichannel heat sinks (MCHSs). Two types of double serpentine minichannel heat sinks are investigated and compared. The first one is a traditional-design MCHS with plate fins, while the second one is a performance-enhanced MCHS design. Three-dimensional conjugate heat transfer models are developed, and the equations governing flow and energy are solved numerically with ANSYS Icepak. The results indicate that the novel MCHS design is found to significantly reduce both the average pressure drop across the minichannels and the total thermal resistance by up to 51% and 8.5%, respectively. Meanwhile, heat transfer enhancement can be obtained for all the rib oblique angles from 13° to 163°, while lowest average pressure drop can be obtained near 90°. The present study provides a new choice for researchers to design more effective MCHSs for the cooling of modern phased-array radar high-heat-flux chips. Full article

Effective thermal management of electronic modules is crucial to the reliable operation of variable frequency air conditioners. For this reason, two types of plate-finned heat sinks of electronic modules were selected. The experiments utilized ceramic heating plates to simulate chip heating, conducted in an enthalpy difference laboratory with controlled environments. Four installation cases were analyzed to evaluate the impact of heat sink orientation, airflow direction, and structural layout. The results showed that when multiple chips were arranged on the same heat dissipation substrate, the heat dissipation process of the chips would be coupled with each other, and the rational layout of the chips played an important role in heat dissipation. In the case of cooling air impacting the jet, the heat dissipation performance of the heat sink was significantly improved, and the heat transfer coefficient of the heat sink was as high as 316.5 W·m⁻²·°C⁻¹, representing a 6.9% improvement over conventional designs (case I: 296.1 W·m⁻²·°C⁻¹). The maximum temperature of the chips could be reduced by 11.1%, which is 10.1 °C lower. This study will provide a reference for the optimization design of the heat sink of the electric control module in inverter air conditioners. Full article

The increasing power density of electronic devices drives the need for lighter, more compact heat dissipation devices. This research determines whether a hollow heat sink filled with fluid outperforms solid heat sinks for heat dissipation. Research on the integration of a heat spreader, heat pipe, and finned heat sink as a single component is limited. The copper and aluminum heat sinks consisted of a 4 × 4 fin array with a volume of 44.5 × 44.5 × 44.5 mm³. The working fluids were water and acetone with a 50% fill volume for the hollow copper and aluminum heat sinks, respectively. Each was tested at nine operating points (varying applied heats and air velocities). The hollow copper heat sink had similar overall heat sink thermal resistance while the hollow aluminum increased by 8% when compared to the solid copper heat sink, and the hollow heat sinks had a 2–9% lower fin array thermal resistance. The weight was reduced by 82% and the mass-based thermal resistance was 77% lower than the solid copper heat sink for the hollow aluminum heat sink. The considerable decrease in mass without significant loss in thermal resistance demonstrates the potential widespread application across technologies requiring low-weight components. In addition, the hollow heat sink design provides comparable or superior thermal performance to previous flat heat pipe solutions. Full article

Thermal management at a high heat flux is crucial for electronic devices, and jet impingement cooling is a promising solution. The heat transfer properties of a rectangular-finned heat sink are investigated under angled and multi-impingement jet configurations in this study. Experiments were conducted with three different nozzle diameters, three different heat sink angles, three dimensionless nozzle-to-heat sink distance ratios, and five different velocity values. As a result, the obtained data are presented as Nu-Re graphs, and the impacts of the parameters on heat transfer (HT) are analyzed. It is concluded that the Nusselt number increases with the increasing nozzle diameter and Reynolds number, whereas it decreases with increasing distance between the nozzle and the heat sink. When comparing the angle values under an identical flow velocity, nozzle diameter, and dimensionless h/d distance experimental conditions, it was found that the Nusselt numbers were very close to each other. Under constant heat flux and for all investigated angles, the highest Nusselt number for the rectangular-finned inclined heat sink was observed at a 10° heat sink inclination, a nozzle diameter of D = 40 mm, a dimensionless distance of h/d = 6, and a flow velocity of 9 m/s. This study deepens the understanding of the heat transfer mechanism of impinging jets and provides an efficient method framework for practical applications. Full article

The global development of LED lighting in all applications for both public and indoor lighting establishes a very important lever for reducing the carbon impact by significantly reducing energy consumption. Smart lighting will therefore constitute an essential lever in the smart city of tomorrow. The latter is more sustainable and less energy-intensive than other light sources, contributing towards the Sustainable Development Goals set forth by the United Nations (SDGs 7 and 11). With its ease of integration, ergonomics, lightness, and high quality of light, this innovative light source has two major qualities: its energy efficiency and its long service life. However, poor thermal management has catastrophic effects on these two essential criteria. This necessarily requires optimizing thermal management and heat sinks. In some cases, thermal models and simulations can lead to considerable calculation times because they implement many parameters. This work therefore aims to reduce the number of these simulations by applying the method of experimental designs (Taguchi) and analysis of variance (ANOVA) to simulations intended to optimize the dissipation of LED luminaires. We applied the method to a simple finned heat sink model for a unit input power and then to a concrete case of a high-power LED. The control parameters and their respective contributions in the proposed model were studied. The ANOVA results corroborated the conclusions of the Taguchi method, demonstrating a strong agreement between these analytical methods, in which the temperature was adjusted by identifying optimal combinations of parameters. The fields of application relevant to this study include both indoor lighting (false ceiling) and confined spaces with severe sealing constraints such as car headlights or the optical blocks of urban luminaires. Full article

To investigate the impact of frost-layer formation on the heat transfer characteristics of cryogenic valves in LNG vessels, this study derived the temporal variation in the valve’s temperature field based on the thermodynamic characteristic parameters of the low-temperature valve. Additionally, a frost formation model was developed for the drip tray. This considered the physical model characteristics of the tray, and the frost thickness was calculated for different times. The morphology of the calculated frost layer was coupled with the low-temperature valve model for heat transfer calculations to explore the influence of the frost layer on valve heat transfer characteristics. The results show that, in the initial stage of frost formation, the frost layer acts similarly to a finned heat sink, enhancing the thermal exchange efficiency at the surface of the drip tray, which results in a temperature increase in the drip tray and stuffing box compared to the frost-free condition. However, as the frost layer grows on the surface of the drip tray, the surface heat transfer resistance increases, gradually diminishing the enhancing effect of the frost layer on the heat dissipation of the drip tray. The results validate the dual role of the frost layer in the heat transfer process of low-temperature valves, providing important insights for the design and optimization of such valves. Full article

The onboard circuits of EV chargers comprise heat-producing electronic devices such as MOSFETs and diodes for switching and power conversion operations. A heatsink must dissipate this generated heat to extend the devices’ life and prevent component thermal stress or failure. This study primarily investigates the optimal heatsink geometry and pin configuration, which offers the most efficient temperature versus cost performance. MATLAB/Simulink (R2024a) was used to model a Level 1 charger using eight MOSFETs and four diodes. Various heatsink geometries were modeled using the ANSYS (2024 R1) Workbench and Fluent software to optimize the sink’s thermal performance. The analyses were performed under transient conditions using natural and forced cooling scenarios. The 2 mm wide plate fin heatsink with 44 fins yielded the best result. Further enhancement of the best-performing naturally cooled model improved the switches and diodes temperatures by 14% and 4%, respectively. The performance of the heatsink was further improved by applying a cooling fan to achieve an up to 25% diode and 40% MOSFET thermal dissipation efficiency. The results of this study show that the most efficient cooling performance and cost are realized when the optimum combination of fin spacing, proximity from the cooling fan, and fin geometry is selected. Full article

This study aims to optimize the thermal performance of pin fin heat sinks by minimizing the maximum temperature of the heat source. Using ANSYS ICEPAK, simulations were conducted for various design parameters, including the number of fins, inlet flow rate, and fin thickness, across circular fins in both inline and staggered arrangements. The circular staggered configuration with 36 fins (3 mm thick) and a flow rate of 6 CFM (Cubic Feet per Minute) achieved the lowest temperature of 34.96 °C, outperforming the inline arrangement. The Taguchi method helped strike a balance between heat transfer and pressure drop, revealing that flow rate has a greater influence when varied compared to the number of fins and fin thickness. An optimal configuration was identified with 36 fins and a flow rate of 4 CFM, which was less sensitive to operational variations. Analysis of Variance (ANOVA) revealed that inlet flow rate significantly impacts heat sink performance, while polynomial regression models demonstrated strong generalization capabilities, with Root mean square error (RMSE) of 8.92%. These findings provide reliable predictive tools and practical insights for optimizing heat sink designs in electronics cooling applications. By utilizing the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method, the coefficient of relative closeness (Cn*) is plotted as a main effect. Referring to the multi-objective optimization-based TOPSIS method, it is found that the attributes are partly from the inlet flow rate (Q) are 63.4% of the number of fins (Nf) (25.05%). Full article

Noah-2100A and HFE-649, as two electronics fluorinated liquids (EFLs) with low saturation temperature, high safety, excellent insulation properties, and low environmental impact, are considered as replacements for the refrigerants with high Global Warming Potential (GWP), such as HFC-134a and HFC-245fa, in electronic cooling system. However, there is still a knowledge gap of boiling heat transfer for these two EFLs, especially in pin-fin microchannel. The effect of inlet temperatures, mass flow rates, and inlet vapor qualities on boiling heat transfer for two EFLs were studied experimentally in this paper. Overall, though the Noah-2100 has a higher pressure drop-in microchannel than HFE-649, Noah-2100A shows a higher overall thermal performance than HFE-649. Newly developed correlations of the Nusselt number (Nu) and pressure drop for two EFLs in a pin-fin microchannel heat sink were also presented. The proposed correlations can achieve a 10% and 11% mean average percentage error for Nu number and pressure drop. Full article

The flow characteristics and thermal performance of circular cylinders with V-shape slots are investigated numerically. The simulation is a two-dimensional incompressible flow that employs the semi-implicit finite volume multi-material algorithm MPM-ICE, which is a module of the Uintah framework. The normalized slot width s₂/D ranges from 0.1 to 0.2, and the corresponding increases in total surface area are from ~99% to ~70%, respectively. Compared to the solid cylinder, the slotted cylinder has the largest total drag reduction of ~67% at s₂/D of 0.2. Meanwhile, although the heat transfer is proportional with the surface area, the thermal performance of the V-shape slot first improves with the slot width, and then declines. The heat transfer improvement has an optimum value of ~192% at s₂/D of 0.15. The overall slot performance, defined by the ratio of the heat transfer to the drag force, is best at 0.175. Full article