Metal Fins Research Articles

Comparative experimental performance research on parameter optimization of foam metal radiators

As a new type of plate fin radiator, foam metal radiators can be widely applied in the automobile and petrochemical industry field. The foam metal fin structure has great influence on the heat exchange performance. In this paper, a parameterized optimization method to optimize the airside heat exchange structure of foam metal has been presented. Comparative experimental performance research on the initial and optimized foam metal radiators have been carried out. Results showed the unit volume heat dissipation rate and airside heat transfer coefficient of the optimized foam metal radiator compared with the initial radiator has a maximum increase of 6.5 % and 1.43 %, respectively, under the airflow rate from 800 m3/h to 2800 m3/h at the ambient pressure of 58 kPa and room temperature. The optimized radiator has the better overall performance at higher airflow rate, where the comprehensive evaluation factor (i.e. JF) of optimized radiator is larger than that of the initial radiator. The optimized radiator has better heat dissipation performance and needs lower fan power consumption under the same gas side resistance. The effectiveness of the parameter optimization method has been validated by experimental results and can be used to optimize the structure of foam metal radiator.

Study on the Effect of Heat Transfer Characteristics of Energy Piles

The thermal performance of energy piles equipped with new metal fins to improve heat transmission is examined in this research. The solid heat transfer module of COMSOL Multiphysics was used to create a 2D numerical model of the energy pile, utilizing the energy pile at a field test site in Nanjing as an example. By contrasting the experimental data, the COMSOL Multiphysics model’s correctness was confirmed. After that, a new kind of energy pile fin was created to improve the heat transfer of the pile. The impact of the new fin type on the energy pile’s heat transfer efficiency was assessed, and the temperature change within the soil surrounding the pile before and after the fin was set was examined by contrasting the parameters of pipe configuration, buried pipe depth, and concrete thermal conductivity. The results indicate that after setting the fins to run for 336 h, the temperature of the concrete area increases by 10.8% to 12.3%, and the temperature of the region surrounding the pile increases by 5.3% to 8.7% when the tube diameter is chosen to be between 20 and 40 mm; The fins maximize the heat transfer temperature between the surrounding soil and the concrete, and as the tube diameter increases, the temperature drops. For 336 h of pile operation, the temperature of the concrete may be raised by 10.8% to 12.3% after the fins are set, and the temperature around the pile can be raised by 5.3% to 8.7%. The heat transmission efficiency of the energy pile can be improved by raising the temperature of the soil surrounding the pile through an increase in the concrete’s thermal conductivity; however, the degree of improvement diminishes as the conductivity rises. It is intended that this study will offer insightful information on the best way to design energy pile heat transfer efficiency.

Effectiveness of a PCM-based heat sink with partially filled metal foam for thermal management of electronics

Electronics often experience overheating, which occurs when insufficient or improper cooling causes temperatures to rise quickly, potentially leading to component failure. Recently, a passive technique utilizing phase change material (PCM)-based heat sinks is suitable for modern electronic cooling. However, due to its low thermal conductivity, Aluminum (Al) foam as a thermal conductivity enhancer (TCE) is used. In this study, a partial filling approach is employed, involving a heat sink designed to cool a protruding electronic component (EC) attached to a metal fin. The enthalpy-porosity method and the thermal equilibrium model are applied. Results show that the efficiency of the heat sink is improved by increasing the filling ratio of the Al foam, thereby reducing the EC temperature by 15.85 °C, shortness the melting time by more than 1000 s, and the overall effective conductivity enhanced by 25 times compared to the case without Al foam. In addition, the optimal partial filling ratio is determined to be 2/3, due to the considerable savings of 33.33 % in material cost and overall heat sink weight. The findings suggest that partial filling is a strategy that can be employed to achieve a more comprehensive performance in thermal management using PCM-based heat sinks.

PCM-based passive cooling solution for Li-ion battery pack, a theoretical and numerical study

We propose in this study a novel cooling solution for Li-ion battery packs based on Phase Change Materials (PCM) and metallic fins placed around each cell. Discharging and charging processes both melt the PCM. To complete the thermal management of the batteries, an intermediary sequence is added for the PCM solidification. During a short timeframe between batteries charging and discharging, a liquid coolant flows through one small channel located within each fin. A numerical model and a theoretical analysis allow to predict the thermal behavior of the battery cells and the PCM liquid fraction changes in time. It is shown that the combination of a passive cooling solution brought by the PCM with the fast period of liquid cooling for the PCM solidification is an effective solution to control the temperature evolution within the battery cells during discharge and charge. The only external energy consumption foreseen comes from the laminar flow of the coolant for solidification during a very short period of time. The findings indicate that the proposed PCM-liquid cooling integration reduces the total energy consumption by 54.9 % (from 0.4406 kJ to 0.1963 kJ) for the 2C discharging-2C charging cycle compared to traditional liquid-cooling strategy.

Precisely regulating thermal deformation behavior of wire electrical discharge machining thin-wall fin via pulsed laser-induced shockwave

The thermal deformation in the process of thin-walled metal fin processed by wire electrical discharge machine (WEDM) is almost unavoidable, which restricts the application of wire electrical discharge machining in the precision machining of thin-walled parts. In this study, a new process of thermal bending deformation regulation by laser-induced shockwave of wire electrical discharge machining thin-wall fin was proposed to obtain low/no deformation thin-wall parts. The thermal deformation of thin-wall In718 metal processed with different wire electrical discharge machining parameters was calibrated, and the law between the thermal bending and the process parameters was obtained. The thermal ablation and laser shock thermal deformation regulation model was established to accurately describe the stress distribution and deformation behavior of thin walls. For In718 thin-wall fin with different thicknesses, the thermal bending deformation could be regulated by laser-induced shockwave. After adjustment, the warpage of all thin walls was only −0.174μm at the lowest, and the thermal deformation could be reduced by 98.35 % at the highest. Laser shock improved the surface integrity of thin walls, increased the surface hardness to 433.9HV, increased by 46.84 %; laser shock also reduced the surface roughness of thin walls to a maximum of 2.67μm, a decrease of 33.58 %. In addition, laser shock could reduce the number of large-size grains, increase the number of twins, refine the impact surface grains to a certain extent, and the particle size was reduced to 7.64μm, which was reduced by 45.62 %.

Waste heat recovery from exhaust gases using porous metal fins: a three-dimensional numerical study

Abstract The objective of this study is to investigate the impact of different porous metal samples on the hydro-thermal characteristics of a single cylinder with porous fins using computational fluid dynamics. Commercially used porous samples with pore densities of 10, 20, and 40 PPI were used in this study for heat recovery from exhaust flue gas. The three-dimensional computational domain with porous aluminium fins attached to a tube over which high-temperature exhaust gas flows in a crossflow arrangement mimics a waste heat recovery system. Computations were performed at Reynolds number of 6000-9000, using the realisable κ-ϵ turbulence model. Three fin diameter to tube diameter ratios (Df/D = 2, 2.5, and 3) were considered. The local thermal non-equilibrium model is implemented for energy transfer, as it is more accurate for a high-temperature gradient scenario in a waste heat recovery system. The foam sample with the highest pore density was observed to have the highest pressure drop due to low permeability. A maximum heat transfer and Nusselt number were achieved for a 40 PPI foam sample due to a reduced flow rate inside the porous zone. The overall performance of metal foam samples at varying fin diameters was evaluated based on the area goodness factor (j/f) and a heat transfer coefficient ratio to pumping power per unit heat transfer surface (Z/E). Analysis of these two parameters suggests using 20 PPI foam at Df/D = 2.

Optimal orientation of efficacy metal fins to enhanced freshwater generation in solar distillers: An experimental study

The pressing issue of water scarcity in remote regions has stimulated the search for simple desalination techniques. Solar distillers represent one of the most important solutions in remote regions for producing freshwater, but they have low productivity. The efficient iron fins represent an effective solution to improve their freshwater productivity. However, due to the negative effect of the shadow resulting from the metal fins, the present study aims to obtain the optimal orientation of efficacy metal fins that achieves the highest productivity for solar stills. To achieve this, three solar distillers were designed and built with identical dimensions. The first distiller has vertically oriented iron fins incorporated with its basin. The second distiller has 45° inclined iron fins incorporated with its basin. But the third distiller is devoid of any iron fins and represents the reference case. Our findings revealed that the inclusion of iron fins, particularly inclined ones, significantly enhanced the yield of the solar still by 48.94 %. In contrast, the enhanced distiller with vertical fins showcased a 33.84 % increase in productivity compared to the reference distiller. Based on these results, we recommend adopting the 45° inclined metal fins to mitigate shading effects and achieve the highest productivity.

Improved Thermal Management of Li-Ion Batteries with Phase-Change Materials and Metal Fins

Improved Thermal Management of Li-Ion Batteries with Phase-Change Materials and Metal Fins

Performance enhancement of porous clay cooler for BIPV applications using hollowed clay structures and metallic extended fins as evaporation and thermal conductivity enhancers

This paper investigates the employing of a passive evaporative cooling approach to mitigate the temperature rise of PV panels within building-integrated photovoltaic (BIPV) systems. The investigation explores enhancing the heat transfer capabilities of composite clay layers by incorporating thermal conductive materials such as iron-oxide and zinc-oxide. This enhancement aimed to improve the overall thermal properties of the composite clay structures, thereby boosting heat transfer rates. Additionally, two distinct designs were evaluated as well: one integrating hollowed clay layer and the other featuring a clay layer with extended fins to enhance both heat and mass transfer rates within the evaporative porous clay structure. A series of experiments conducted under real conditions using prototyped building rooms to simulate real BIPV systems to assess the cooling performance of the presented scenarios. The results revealed that the hollowed clay layer achieved the most substantial decrease in PV panel temperature, with a reduction of 16.5 % compared to the findings with a solid clay layer. In contrast, the composite Iron-oxide/clay layer demonstrated the smallest decrease in PV temperature at 11 %. Moreover, utilizing the hollowed clay structure led to a 6.3 % increase in average PV output power, as well as around 4.5 % enhancement in average photovoltaic’s efficiency compared to the outcomes observed with the solid clay layer. Moreover, incorporating the hollowed clay layer resulted in the most significant decrease in the building's annual load, achieving a reduction of 79.6 %. This signifies approximately a 2 % higher enhancement in cooling capabilities compared to utilizing solid clay layer. Further, the cost of electricity production decreased by 7.7 % (from 0.104 $/kWh to 0.096 $/kWh) following the incorporation of the hollowed clay layer, while the payback time was reduced by roughly 0.8 years compared to utilizing the solid clay layer and by 1.7 years in comparison to the non-cooled BIPV system.

Melting of a phase change material in a rectangular cavity in the presence of metallic fins

The melting of the phase change material (PCM) octadecane, confined in a rectangular cavity heated from the bottom, is numerically studied. Simulations are performed through finite element software in order to analyze the impact of metal fins within the enclosure on the melting time. The results are analyzed in terms of the time-dependent position of the melting front, time-dependent average liquid fraction, and time needed for the PCM melting. The obtained outcomes highlight how, with a low number of metallic fins, the initial melting regime dominated by conduction at a certain time gives way to a convective melting regime characterized by Rayleigh–Bénard cells, in full agreement with the results of the theoretical analysis. On the contrary, with a high number of metallic fins, conduction is the only mechanism that governs heat transfer and the rapid melting slows down when the phase change front reaches the top of the fins. More specifically, the addition of the fins within the cavity yields a reduction in the time needed for the complete PCM melting up to 90% in the analyzed cases. The reported results provide new insights regarding the heat transfer mechanisms involved in PCMs melting within bottom-heated enclosures.

Investigating the performance improvement of lithium-ion battery cooling process using copper fins and phase change materials (PCMs)

This study investigates utilizing phase change materials (PCMs) along with metallic fins for passive cooling of lithium-ion batteries. PCMs have low thermal conductivity, which is enhanced by incorporating copper or aluminum fins. Numerical simulations using ANSYS FLUENT's Solidification & Melting solver in an axisymmetric configuration are performed. PCM cooling outperforms air cooling, providing up to 15 °C lower maximum battery temperatures as long as PCM remains solid. The findings from the analysis of air cooling versus cooling with PCM demonstrate that the use of phase-change materials enhances battery cooling performance for a specific duration, provided that these materials do not fully liquefy. Adding fins further improves cooling for 0.2 mm thickness, 6 copper fins of 11.67 mm height give optimal performance with 8 °C lower peak temperatures than without fins. Copper fins outperform aluminum due to 60 % higher thermal conductivity but have 3X higher density. For longitudinal fins, 4 fins of 10 mm height perform better than 10 fins of 3 mm height. With high conductivity PCMs like paraffin wax (0.242 W/m.K), varying fin count has minimal impact as heat distributes rapidly. This study establishes guidelines for optimizing PCM-fin geometries and materials to maximize passive lithium-ion battery cooling performance.

Numerical simulation of heat pipe solar system combined with finned thermal storage unit incorporating mixture of nanoparticles and paraffin

The core aim of this investigation is to simulate the melting of paraffin within a solar heat pipe unit combined with thermal storage unit, while taking into account the presence of metallic fins. To enhance system performance, Multi-Walled Carbon Nanotube (MWCNT) nanoparticles were blended into the paraffin material (RT82) using a homogeneous mixture approximation. The temperatures of the heat pipe and inner walls were derived from previous experimental research. Three distinct fin arrangements were utilized, and simulations were carried out employing numerical method. Validation procedures were undertaken to verify the accuracy of the modeling and the applied approximations, relying on both prior experimental data and numerical publications. The investigation presents data on the liquid fraction (LF), temperature (T), and stream function for diverse configurations. This holistic approach seeks to deepen comprehension of the interactions among these elements within a solar collector system, offering vital insights for performance optimization. The outcomes demonstrated a notable improvement in LF, increasing by roughly 15.15% at t = 1200s with the integration of MWCNT. Furthermore, with the passage of time from 400 s to 1200s, the incorporation of additives results in a notable rise in LF and T, demonstrating enhancements of approximately 97.74% and 130.8% correspondingly. Notably, the utilization of fins positioned at a 90o angle expedites the melting process, yielding a 38.24% LF increase compared to the base case at t = 1200s. Moreover, the impact of fins demonstrates a 3.32% increase over time. In essence, these results emphasize the effectiveness of incorporating MWCNTs and fine-tuning fin configurations to accelerate the melting process, offering valuable insights for the progress of solar thermal systems.

Enhancing the internal thermal conductivity of hydrogel for efficient passive heat dissipation: Experimental study of a surface simulating a cooled photovoltaic panel

Over 75 % of the absorbed solar energy by photovoltaic (PV) panels is dissipated as heat, leading to a substantial increase in their operating temperature. The temperature rise can adversely affect the energy efficiency and longevity of PV modules. Consequently, efficient cooling technologies are urgently required for PV panels. In this study, an enhanced passive cooling strategy for PV panels was proposed based on evaporative cooling, which employed a composite structure consisting of metal fins and hygroscopic salt hydrogel. The hydrogel demonstrated a water sorption capacity of 1.87 g g−1 after a 16-hour moisture absorption at 25 °C and ∼70 % relative humidity (RH). The fin-hydrogel structure demonstrated an average evaporative cooling power of ∼185 W m−2 over 10 h, resulting in a temperature reduction of ∼16 °C for the simulated PV module under an input heat flux of ∼1000 W m−2. Furthermore, durability and regeneration tests confirmed the feasibility of the fin-hydrogel structure for long-term PV cooling through cyclic water harvesting and release. This innovative cooling strategy offers promising opportunities for effective thermal management and broadens the scope of hydrogel applications, especially in dry areas with low humidity.

Smart fin with automatic evaporation and regeneration for thermal management of high heat flux electronics

The high temperature of modern electronic devices poses great challenges to the safety and reliability of applications. Reasonable and effective control of device operating temperature for enhancing device performance and promoting the development of the electronics industry has a positive effect. Here, an innovative and efficient passive cooling technology is proposed to reduce the device temperature using polymerized metal fin and smart hydrogel to form smart fin. The smart fin carries away the waste heat generated by the device through evaporation and regeneration is accomplished by capturing water molecules from the environment. The smart fin is demonstrated to low down the temperature of a heater with heat flux of 2900 W/m2 by 48.3 °C and restores to its initial state after 160 min. At a threshold temperature of 60 °C, it promoted the maximum usage power by 49.4%. The evaporation and regeneration capacity of the smart fin can be controlled by ambient temperature, relative humidity, and smart hydrogel thickness. Specifically, high temperatures promote water evaporation and absorption, high humidity suppresses evaporation but favors absorption, and excessive thickness impedes water transport. This thermal management strategy with simple structure, low-cost, and easy-preparation is expected to become a universal technology in the electronics industry.

Boosting thermal regulation of phase change materials in photovoltaic-thermal systems through solid and porous fins

This study explores the integration of porous fins with phase-change materials (PCM) to enhance the thermal regulation of photovoltaic-thermal (PVT) systems. Computational simulations are conducted to evaluate the impacts of different porous fin configurations on PCM melting dynamics, PV cell temperatures, and overall PVT system effectiveness. The results demonstrate that incorporating optimized porous fin arrays into the PCM region can significantly improve heat dissipation away from the PV cells, enabling more effective thermal control. Specifically, the optimized staggered porous fin design reduces the total PCM melting time and decreases peak cell temperatures by about 5°C . This is achieved by creating efficient heat transfer pathways that accelerate the onset of natural convection during the PCM melting process. Further comparisons with traditional solid metallic fins indicate that while solid fins enable 12.2% faster initial melting, they provide inferior long-term temperature regulation capabilities compared to the optimized porous fins. Additionally, inclining the PV module from 0° to 90° orientation can further decrease the total PCM melting time by 13 minutes by harnessing buoyancy-driven convection. Overall, the lightweight porous fin structures create highly efficient heat transfer pathways to passively regulate temperatures in PVT systems, leading to quantifiable improvements in thermal efficiency of 16% and electricity output of 2.9% over PVT systems without fins.

Experimental and numerical study on the effect of the intelligent memory metal fin on the melting and solidification process of PCM

Experimental and numerical study on the effect of the intelligent memory metal fin on the melting and solidification process of PCM

Experimental and numerical investigations of an open-cell copper foam (OCCF)/phase change material (PCM) composite-based module for satellite avionics thermal management in a thermal vacuum chamber (TVC)

Small satellites' thermal control in the space environment is crucial. Phase change materials (PCM) are promising options for satellite thermal management in space thermal conditions. The current work provides an experimental and numerical investigation of a thermal control module (TCM) using an open-cell copper foam (OCCF)/PCM combination. The experimental tests were carried out in a thermal vacuum chamber (TVC), which simulated the vacuum space environment. The PCM thermal conductivity was boosted using OCCF and aluminium fins. The metallic parallel fins divided the heat sink into six cuboid cavities and were filled with PCM. Two samples with different pores per inch (PPI) of OCCF were adopted, one with 10 PPI and the other with 20 PPI. For the experimental work, the adopted PCM was SP 31. Two levels of heating loads were applied to the TCM: 10 W and 7 W. The numerical model was verified using the experimental work findings. The experimental work concluded that the PCM capsulation sealing is a dominant factor for successful capsule design under vacuum operation. The thermal conductivity enhancers (TCEs) remarkably improved the thermal management performance of the PCM. The case with PCM reported a reduction in the maximum temperature by about 43.67 % and 41.4 % at 7 W and 10 W, respectively, relative to the case without PCM. The PCM/fins combination could improve the PCM performance and mitigate the maximum temperature from 41.7 °C to 39.6 °C with a reduction percentage of 5 %. The OCCF reported better thermal performance than the metallic fins. The OCCF with 10 PPI decreased the PCM maximum temperature by 10.3 %. The OCCF with 20 PPI reported a reduction in the PCM maximum temperature by 13.8 % at 10 W heating power.

Plastic 3D Printing in Adsorption Cooling: A Proof‐of‐Principle Module

Plastic 3D printing allows the replacement of metal parts in a water/silica gel adsorption heat transformer module and its rapid manufacturing at low cost. This research investigates a simple design using three finned metal heat exchangers (HEXs) enclosed in one plastic 3D‐printed vessel. The dynamics of a conventional packed bed adsorber of Siogel silica gel grains with thermal response method is first identified to establish a benchmark case and allow to focus only on the challenges introduced by plastic 3D printing. Final testing of the device across a range of operating conditions and cycle times representative of cooling, desalination, and intermediate shows the adsorber follows an unconventional thermodynamic cycle. Generation of larger powers is achievable by coupling multiple small modules.

Rayleigh–Bénard type PCM melting and solid drops

In this paper we document both theoretically and numerically the melting of PCM in an enclosure heated from the bottom, in the presence of vertical metallic fins. We start with the analysis of the PCM melting in the absence of fins to discover the main scales of the problem, stressing the occurrence of Rayleigh-Bénard cells generated during the convection regime of melting. We continue with predicting the impact of fins on the development of the melting interface. The numerical experiments allow to understand the impact of the aspect ratio between the height of the enclosure and the distance between fins on the melting dynamics. They highlight the existence of solid drops for a certain range of aspect ratios when the horizontal flow channels in the convective loops along the fins become in contact, and they show how the solid drop is dragged downward to finish melting on the heated bottom of the enclosure.

Evaluating the impacts of fin structures and fin counts on photovoltaic panels integrated with phase change material

Metal fins synergized with phase change materials (PCMs) provide good thermal management for photovoltaic (PV) panels, and the performances largely depend on the shapes and counts of the fins, and the layouts of the cavity. This work first compares the thermal behaviors of one fractal fin or one straight fin in the cavity with height H (mm)-width W (mm) of 80-75, 100-60, 120-50, 150-40, and 200-30, respectively. The results show that one fractal fin can accelerate the PCM melting and further lower the PV temperature by 2 °C than one straight fin. Moreover, a more desirable cavity with the dimension of 120-50 is clarified by comparing the PV panels average efficiency during 0∼180 min versus the energy input. Next, comparisons of the fin counts N = 1, 2, 3, and 4 reveal that raising the fin count N to 2 reduces the PV panel temperature by 2.3 °C, and the fin counts cause most of the difference. Ultimately, a suitable PCM thickness of 40 mm is selected by considering the PV panel temperature along with the weight and cost of the systems. This study aims to promote the development of finned PV panels integrated with PCMs.