Fin Arrangement Research Articles

Experimental study of subcooled flow boiling in microchannel heat sinks integrated with different embedded pin fin arrays microstructures

The optimized microchannel heat sinks could enhance flow boiling for effectively tackling the electronics cooling. The flow boiling experiment for three microchannel heat sinks integrated with different layouts of entrenched pin fins is conducted at flow rate of 273.6–456 kg/(m2.s) and inlet subcooling of 35∼50 K. The overall/local heat transfer features, pressure drop and boiling mechanism are studied. The hybrid pattern presents earliest initial boiling and lower superheat than the microchannel heat sink with uniform pin fins arrangement at moderate and large flow rates. The trend of overall and local HTC (heat transfer coefficient) is similar, which occurs peak at onset nucleation boiling, and then decreasing with increasing heat flux. At the largest flow rate, the hybrid pattern exhibits 2.7–3.5 times peak HTC promotion than other patterns. As for lowest flow rate, the hybrid pattern does not manifest remarkably superior performance due to downstream vapor cores clogging effect. The hybrid pattern shows largest pressure drop, and the smaller inlet subcooling manifests inferior heat transfer and resistance performance. The comprehensive performance factor (CPF) is proposed, and the pattern with uniform small-sized pin fins shows optimal CPF especially for low flow rate, which is considerable compared with the reference heat sink structures until high heat flux. This study may provide some insight into the design of microchannel for flow boiling heat dissipation.

Numerical Study on the Effect of Heat Source and Fin Arrangement on the Melting Performance of Phase Change Materials in a Latent Heat Storage System

Numerical Study on the Effect of Heat Source and Fin Arrangement on the Melting Performance of Phase Change Materials in a Latent Heat Storage System

Optimization of the annular fin arrangement in phase change heat storage units based on response surface methodology

Latent heat thermal energy storage (LHTES) technology is of increasing industrial interest due to its advantages such as high heat storage density and near-constant temperature during the phase change process. However, the latent heat storage technology is impacted by the low thermal conductivity of the phase change material (PCM), leading to delays and heat loss in the heat transfer process within LHTES. This limitation reduces the efficiency of heat transfer and diminishes the performance of the heat storage unit. To address this issue, this paper employs numerical simulation and response surface methodology to investigate different types of annular fin phase change heat storage units, aiming to derive the optimal configuration for enhancing unit performance. Therefore, the effect of fin type and number on the melting and solidification process is analyzed in detail. The research results indicate that among the five different types of fins studied, the total time required for the unit to complete melting and solidification is the least with type “e” fins, only 51.78 h, demonstrating that type “e” fins have the best effect on improving unit performance. For type “e” fins, when the number of fins n is 15, it can most effectively shorten the melting and solidification time of the phase change heat storage unit, reducing it to only 47.81 h. In addition, the response surface methodology was utilized to derive the optimal fitting formulas for different types of annular fins and to validate these formulas, and the error between the validation analysis and the numerical simulations was within 5%, which confirms the reliability of the fitting formulas developed in this study. This approach facilitates the selection of various annular fin models for subsequent experimental and simulation studies, thereby reducing the time and cost associated with model selection.

Study on the flow and heat transfer characteristics of a hybrid nanofluid jet impingement microchannel heat sink with airfoil fins

AbstractDue to the continuously increasing power density of electronic devices, the improvement of the temperature uniformity and the reduction of the irreversible energy losses became crucial in these studies on enhanced cooling capacity of the heat sinks. In this paper, a jet impingement microchannel heat sink with airfoil fins (AF‐JIMHS) is proposed. The AF‐JIMHS with reversed fins arrangement has very high comprehensive heat transfer performance. The increase of the internal tangent circle radius and chord length of fin can improve the temperature uniformity of the AF‐JIMHS bottom surface and reduce the irreversible energy losses, at the expense of reducing its comprehensive heat transfer performance. Although the increase of the tangent arc length of fin reduces the temperature uniformity and increases the irreversible energy losses of the AF‐JIMHS, it improves the comprehensive heat transfer performance in a specific parameter range. The increase of fin height improves temperature uniformity of the AF‐JIMHS, while reducing its irreversible energy losses and improving its comprehensive heat transfer performance. Compared with the AF‐JIMHS with uniform height fins, the one with decreasing height fins has higher comprehensive heat transfer performance and lower irreversible energy losses. Moreover, the AF‐JIMHS with increasing height fins has better temperature uniformity.

A numerical study of the performance of solid oxide fuel cell with bi-layer interconnector

Solid oxide fuel cell (SOFC) has attracted wide attention because its efficiency is not limited by the efficiency of Carnot cycle. The structure of flow channel in SOFC has great effects on the internal mass distribution, which influences current density. In this paper, the height of flow channel and the position, arrangement, number and height of the fin which is placed in channel, are changed to get different structures of bi-layer interconnector, and they are applied to three layers SOFC stack. The effects of each structural parameter on the current density are studied by numerical simulation. The results show that, increasing the number of fins and bi-layer interconnector height can make more reactant gas enters the electrode. In addition, compared with the conventional structure, the current density can be increased by the bi-layer interconnector up to 31.256%, and the bi-layer interconnector structure could save n-1 layers of interconnector, which reduces the volume of SOFC stack. Among the five structural parameters, the position of fins has the least influence on temperature distribution and current density, while the arrangement of fins has the highest influence on volume current density, reaching 30%. Using a staggered arrangement and higher bi-layer interconnector can also improve the temperature distribution.

Innovative configurations for heat sink integrated with piezoelectric fans

Piezoelectric (PE) fans are gradually replacing conventional axial flow fans in the field of heat dissipation for microelectronics due to small size and high efficiency. However, the flow characteristic of PE fans was seldom considered when arranging heat sink fins, which could not utilize the fans’ advantages. Here, the design of fin arrangement based on the transient flow field generated by the vibration of dual PE fans in the channel was calculated and analyzed by CFD simulation and dynamic grid technology. Four zones with different flow field characteristics were found: Zones 1 and 4 which located inlet and outlet of the channel were Parallel flow zone. Zone 2 with vortices corresponds to the area ranges from the waist of blades to middle section of the channel was Multiple vortices flow zone. Zone 3 with high-speed vortices and jet flows corresponds to the area ranges from middle section of the channel to halfway downstream of blades region was Diffuse flow zone. Innovative configurations of heat sinks where fins arranged at the inlet and surrounding blades were designed according to the flow field characteristics: the loss of high-speed airflow to the inlet was prevented effectively and heat dissipation in the downstream heat sinks was dispersed by fins arranging in Parallel flow zone and Multiple vortices flow zone. The development and merging of high-speed vortices were strengthened by the inhomogeneous pin-fins arranging in Diffuse flow zone. The optimal coordination between the velocity field and the temperature gradient field among innovative configurations was found based on the field coordination analysis. Heat transfer performance was enhanced by new designs where the average temperature compared to conventional heat sink with PE fans was reduced by 16.7°. Our work provided a new fins arrangement to achieve uniform temperature distribution and high heat transfer performance for heat sink integrated with PE fans and would benefit the application in thermal management of high power devices integrated with PE fans.

Melting performance of Molten Salt with nanoparticles in a novel triple tube with leaf-shaped fins

Energy demand has greatly increased today and phase change storage technology is rapidly growing due to its renewable nature. This study explores a new Triple Tube Heat Exchanger (TTHX) model, which divides phase change materials (PCMs) into two regions to improve the connection between TTHX and PCM, to improve the thermal conductivity of PCMs with different fins' number, arrangement, and angle, consequently enhancing thermal storage efficiency. A more efficient exchanger is developed by using Molten Salt as PCM and adding TiO2 and Al2O3 nanoparticles with different concentrations. Liquid fraction, temperature, and velocity obtained from numerical simulation are employed to characterize thermal storage efficiency. ANSYS 2022R1 is used for pre-modeling and numerical computations. The simulation results are turned into graphs and charts for PowerPoint and Origin analysis. We find that PCM's heat transfer efficiency is increased by 34.3 % when effective fins are added, and the addition of 5%TiO2 further increases it by 8.73 %. With the addition of Al2O3 and its concentration variation, combined with the effective fins, the heat transfer efficiency of the PCM can be enhanced by 40.73 %.

Effects of radial fin arrangements on the thermal performance of turbulent liquid jet impingement heat sinks: Experimental and numerical approach

The combination of fins and jet impingement is a highly effective method for enhancing thermal performance in electronic cooling. The arrangement of fins significantly influences the thermohydraulic characteristics of heat sinks. A comprehensive analysis comparing the impact of different radial fin arrangements in confined jet impingement is crucial for a deeper insight into their thermohydraulic performance. This study presents experimental analyses of heat sinks with smooth surfaces and radial straight fins in the Reynolds number ranged from 4300 to 15,500 and the heat flux ranged from 45 to 105 W/cm2. Then a numerical study is conducted on the radial straight and curved fin arrangement to investigate the effects of different radial fin arrangements on the performance of jet impingement heat sinks. The results demonstrate that the use of fins improves heat sink performance by up to 27 % compared to smooth surfaces. The numerical model, employing the SST k-ω turbulent model, shows strong agreement with experimental findings, with a maximum deviation of 9.1 % for the heat transfer coefficient, well within the uncertainty range. Comparing radial straight and curved fin arrangements numerically, the straight fin arrangement exhibits superior thermal performance by up to 9 %. Additionally, the pressure drop for both configurations remains nearly identical. The findings of this research suggest the use of radial straight fin arrangements in annular jet impingement heat sinks over radial curved fin arrangements.

Melting performance of PCM with MoS2 and Fe3O4 nanoparticles using leaf-based fins with different orientations in a shell and tube-based TES system

Phase change materials (PCMs) are frequently utilized in the thermal sector, especially for thermal energy storage (TES) applications. The purpose of this study was to analyze the thermal efficiency and melting characteristics of a leaf-vein-shaped fin in a triplex tube heat exchanger. The analysis focused on the use of pure molten salt PCM and a combination of molten salt PCM with MoS2 and Fe3O4 nanoparticles. The study utilized ANSYS Fluent software to conduct numerical simulations and analyze seven distinct fin arrangements. The simulations were employed to visualize and examine the liquid fraction, temperature, and fluid velocity. The findings indicated that the leaf-vein fin shape greatly improved the dispersion of liquid fraction, average temperature, and velocity in comparison to alternative fin designs. The addition of MoS2 and Fe3O4 nanoparticles significantly enhanced the melting and thermal characteristics of the PCM as a result of heightened thermal conductivity. This showcases the capability of the leaf-vein fin design and PCM nanocomposites to enhance the efficiency of thermal energy storage in triplex tube systems. About 2500 s PCM melt about 36% for case A, but melting rate enhance up-to 55% using nano particles. Melting rate enhance 91% in 1000 s in case of G using 8 fins as compare to case A having no fins.

Investigation of the thermal-hydraulic characteristics of SCO2 in a modified hybrid airfoil channel

The performance of printed circuit heat exchangers (PCHE) is critical to ensuring the efficiency and compactness of supercritical carbon dioxide (SCO2) Brayton cycle systems used in advanced nuclear energy. In order to improve the performance of the airfoil fin channel PCHE, the effect of the airfoil fin size on the channel performance is investigated and the effect of the airfoil fin arrangement parameters on the channel performance is analyzed by the Taguchi method. Particularly, a modified hybrid airfoil fin channel adapted to the changes in thermophysical properties of SCO2 is proposed. The results show that the heat transfer characteristics of the PCHE channel are enhanced and the flow characteristics are weakened with the reduction of the airfoil fin size, and the comprehensive performance firstly increases and then decreases. Taking the comprehensive performance of the channel as the optimization objective, the best combination of airfoil fin arrangement parameters is 2 mm for transverse spacing, 10 mm for longitudinal spacing, and 4 mm for staggered spacing. Compared with the traditional airfoil finned channel, the modified hybrid airfoil fin channel has significantly improved the comprehensive performance by 2.8%–13.2 %.

A computational search for the optimal microelectronic heat sink using ANSYS Icepak

The efficient thermal management of microelectronic devices is crucial for their reliability and performance. Heat sinks, particularly those with inline and staggered fin arrangements, are vital in achieving this goal. This study leverages the advancements in computational fluid dynamics (CFD) software to explore the optimal heat sink design for microelectronic devices. While prior research has extensively investigated heat sink design, this work offers novelty by employing ANSYS Icepak software for simulations. This approach enables a comprehensive thermal performance and pressure drop analysis for two distinct fin cross-sections. The study investigates heat sink assemblies housed within a confined space, simulating a realistic operating environment for microelectronic devices. The heat sink is designed to cool a single heat source (chip) mounted on a substrate board. In this paper, two types of fin sections, circular and conical, are studied for two types of fin configurations, inline (IA) and staggered (SA), which are analysed with 36 fins in each case. Each fin is constructed from aluminium and has specified dimensions. Air serves as the cooling fluid within the cabinet, dissipating heat generated by the chip. When comparing the performance of circular pin and cone fins at the same power and mass flow rate, the results indicated that the maximum temperature for circular pin fins is 0.46% of the maximum temperature for cone fins, and they have a higher pressure drop, especially for staggered arrangements. Moreover, the maximum temperature for staggered arrangements is lower than that for inline configurations by a factor of up to 1.17% and 2.035% for circular fins and cone pin fins, respectively. This article focuses on a deep understanding of the design of microelectronic cooling systems. It aims to continuously improve pressure and thermal efficiency by maintaining the minimum limits of pressure drop within the confined space and obtaining the optimal configuration for efficient heat dissipation.

Expression of Concern for article entitled “Numerical simulation of dimensions and arrangement of triangular fins mounted on cylindrical lithium-ion batteries in passive thermal management”

Expression of Concern for article entitled “Numerical simulation of dimensions and arrangement of triangular fins mounted on cylindrical lithium-ion batteries in passive thermal management”

Multi-objective optimization study of airfoil fin printed circuit heat exchanger with tip gap based on machine learning

The printed circuit heat exchanger (PCHE), a compact and highly efficient device, is capable of operating effectively under demanding conditions, which makes it ideal for supercritical CO2 Brayton cycles. In this study, we present a novel airfoil fin PCHE with tip gap, and conduct multi-objective optimization on the tip gap and arrangement of airfoil fins based on the analysis of the supercritical CO2 flow and heat transfer characteristics. We conduct a parameter design using Design of Experiment to examine the impact of the dimensionless design parameters, including the horizontal number (ζh), staggered number (ζs), vertical number (ζv), and gap number (ζg). To forecast the flow and heat transfer performance, we utilize a neural network model called Particle Swarm Optimization-Back Propagation (PSO-BP). We employ the non-dominated sorting genetic algorithm II to obtain the Pareto optimal front by utilizing ζh, ζs, ζv, and ζg as variables for optimization, and the volumetric heat transfer coefficient (hv) and Fanning friction factor (f) as objectives for optimization. The results find that the utilization of tip gap can enhance heat transfer while reducing flow resistance. The PSO-BPNN model exhibits higher prediction accuracy and excellent generalization ability compared with traditional BPNN model. The VIKOR and TOPSIS methods identify compromise schemes with excellent thermal-hydraulic performance. The mechanism of heat transfer enhancement can be elucidated using the principle of field synergy.

Investigation of Thermal Performance of Optimized Tree-Shaped Fins in Latent Heat Storage Units

An innovative tree-shaped fin is proposed to address the problem of low thermal conductivity of phase change materials (PCMs) in latent heat energy storage units. Numerical methods are applied to investigate the thermal properties of the melting process of PCMs. This paper investigates the effects of fin arrangement, fin geometry parameters, and temperature of the heat source on melting characteristics of PCMs in the latent heat energy storage unit. Results show that the melting time of PCMs with the inwardly-tilted fins at the top increases by 21.3% compared to the outwardly-tilted fins at the bottom. The response surface methodology is adopted to obtain the fin parameter combination with lower quality and better performance. The optimal fin dimensions are a thickness of 1.06 mm, a length of 3.38 mm, and a spacing of 12.61 mm. The reduction of the ambient temperature from 35 °C to 30 °C increases the melting time of the latent heat energy storage unit by 85%, and from 35 °C to 40 °C decreases the melting time by 29%.

Optimization of fin arrangement in solar thermal storage devices and convolutional neural network modeling

Solar energy, a renewable and eco-friendly source, faces challenges in aligning energy production with storage durations. Phase change materials (PCMs) effectively tackle this issue, yet their poor thermal conductivity limits solar thermal storage device performance. Conventional solutions involve adding fins, but limited volume compromises overall heat storage capacity. Our study enhances device performance by rearranging fins while maintaining the same area. The H/R = 0.5 fin arrangement with equal spacing significantly improves heat storage, reducing total melting time by 54.31% with a higher entropy value. Further, arranging five fins, predominantly in the lower part, shortens PCM melting time without compromising upper material melting, enhancing device temperature uniformity. Utilizing computed data, we trained a Convolutional Neural Network (CNN) model, maintaining a maximum error within 5%, with an actual maximum error of only 1.56%. The efficacy of CNN in addressing prediction challenges is noteworthy, showcasing improved solar thermal storage device performance.

Theoretical and experimental investigations on the effect of double pass solar air heater with staggered-diamond shaped fins arrangement

This study presents the research study, both theoretical and experimental, on the effect of double pass solar air heater (DPSAH) using staggered-diamond shaped fins effects. Diamond shaped fins are considered to have the potential to improve the convective heat transfer and increase energy efficiency as well. Forty number of diamond shaped fins have been used in this experiment which have been fixed to the plate absorber where there are four mass flow rates (0.0104 kg/s, 0.0157 kg/s, 0.0209 kg/s, 0.0261 kg/s) used and three variations of solar radiations (600 W/m2, 800 W/m2 and 1000 W/m2). The effect of mass flow rates, solar radiation and outlet temperature has greatly affected the overall performance of DPSAH with staggered-diamond shaped fins. For the computational domain fluid, the configuration of mass flow rates and solar radiation is analyzed using COMSOL Multiphysics 5.6.1, hence the actual experiment has been carried out based on the simulation results. The highest thermal efficiency obtained for experiment and simulation were 59.34% and 62.01% for mass flow rates of 0.0261 kg/s using solar irradiance of 1000 W/m2.

A conjugate heat transfer investigation of outer-wall cooling performance in double-wall vane pressure side

Double wall cooling has significant potential for high-pressure turbine vane cooling technology. Geometric parameters of the double-wall vane play a crucial role in determining the cooling performance. This paper presents a double-wall cooling model with five outer wall thicknesses and three injection angles, using the curvature of the actual pressure side of the engine as a reference. The overall cooling effectiveness is investigated over the range of blowing ratio from 0.5 to 2.5. Results indicate that, at injection angles of 20° and 30°, an outer-wall thickness of 1.5D f maximizes the combined benefits of film cooling and thermal conductivity in solid domains. At an injection angle of 40°, the blowing ratio becomes a determining factor in selecting the optimal outer wall thickness. Additionally, a reasonable arrangement of pin fins promotes a more uniform outer wall temperature distribution. A thinner outer wall at higher blowing ratios provides optimum overall cooling effectiveness.

Heat Transfer Enhancement of Microchannel Heat Sink Using Sine Curve Fins

In this study, numerical simulations are conducted to investigate the effects of initial models (parallel and symmetrical arrangement) using interruption fins on the flow and heat transfer characteristics of microchannel heat sink (MHS). The results indicate that MHS with symmetrical fin arrangement has a higher Nusselt number and lower thermal resistance. The vortices perpendicular to the flowpath is the main factor of affecting the heat transfer characteristics. Because of the higher vorticity, the channel with symmetrical fins achieves higher heat transfer performance. To further improve the heat transfer performance, three modified models (models III–V) are obtained by adopting the methods of staggered, reducing fin quantity, and adding pin fins, respectively. The staggered arrangement of fins can deepen the secondary flow in the channel, and the additional vortices are formed with adding pin fins, which can enhance heat transfer capacity in models III and V. On the other hand, reducing the number of fins can damage some vortices, which can actually reduce heat transfer performance. It is worth noting that both the staggered fins and the pin fins significantly increase the pressure drops of the channel, while reducing the fins number leads to an obvious decrease in the pressure drop.

Influence of a Built-in Finned Trombe Wall on the Indoor Thermal Environment in Cold Regions

This study focuses on energy conservation, reducing the amount of energy consumed to heat a room, and decreasing the intensity of carbon emissions. The research object is a room heated by a floor with a built-in finned Trombe wall (TW) located in Lanzhou, Gansu Province. ANSYS software was employed to conduct a simulation study on parameters such as fin height, transverse spacing, longitudinal spacing, arrangement mode, and fin apex angle. The simulation results were used to determine the fin parameters’ thermal impact on the TW’s thermal performance, including with respect to a room’s thermal environment (TE). The results show that the heat transfer performance of a TW with respect to the thermal environment of a room is the greatest when the height of the heat-absorbing surface is 20 mm, the transverse spacing is 0.20 m, the longitudinal spacing is 0.533 m, and in-line 90° top-angle fins, that is, isosceles right triangle fins, are used. The average Nu number of the fin-type TW is 154.75. Compared with the average Nu number of the finless TW, which is 141.43, the average Nu number increases by 13.32 due to the addition of fins. The optimized fin-type TW has 7.77% higher convective heat supply efficiency than the finless TW. Although the PMV-PPD results of the two TW-type rooms are not very different, the comfort period of the fin-type TW room is longer. At the same time, the LPD3 of the non-finned TW and the finned TW rooms is less than 10%, the wind speed at the head and ankle is less than 0.12 m/s, the air gust sensation is not strong, and the thermal comfort is good, indicating that the addition of fins is beneficial to the improvement of indoor thermal comfort. Compared to standard rooms, finless TW rooms and fin-type TW rooms have energy-saving rates of 36.38% and 44.63%, respectively. Thus, fin-type TW rooms’ energy saving rate is 8.25% higher, resulting in effective savings in heating energy consumption. Therefore, the indoor TE and auxiliary heating conditions are improved, and the integration of solar building technology can be facilitated, which offers significant reference value for energy transformation.

Study on Flow and Heat Transfer in Supercritical CO2 in Micro-channel Heat Exchanger

In order to investigate the flow and heat transfer performances of supercritical CO2 in the PCHE, a two-dimensional micro-channel heat transfer model was established. The impacts of the airfoil fin arrangement on flow and heat transfer of supercritical CO2 in a PCHE were studied using Computational Fluid Dynamics software. The results show that the transfer efficiency of PCHE can be effectively improved by reducing the abeam and vertical distances between airfoil fins. However, the pressure drop of supercritical CO2 flow in the microchannel reduces with an increase in abeam and vertical spacing distances.