Number Of Fins Research Articles

Artificial neural network-based cooling capacity estimation of various radiator configurations for power transformers operated in ONAN mode

Power transformers submerged in oil are universally acknowledged as very useful elements in electrical power networks. A fraction of the electrical energy involved in the conversion from high to low voltages is lost as thermal energy, which is produced inside the transformer's windings and core. The effective dissipation of heat is of paramount significance and can be accomplished through the strategic installation of radiators on the tank. This study aims to examine the total cooling capacity of a radiator employed for cooling a power transformer operating in oil, natural air, and natural mode. The investigation is conducted by varying the design parameters, specifically the number of fins per radiator and the radiator length. The study also utilizes computational fluid dynamics results to achieve a substantial convergence with experimental findings. In the context of the verification study conducted for a specific study point, it was found that the simulation outcomes at a mass flow rate of 0.15 kg/s corresponded to about 7.4 % of the experimental results. Additionally, the cooling capacity value obtained was 7.2 %. In the context of machine learning, the performance of the numerical approach was assessed by employing the Bayesian regularization method. The evaluation revealed that the margin of deviation, mean squared error, and coefficient of determination (R2) metrics yielded values of −0.001 %, 1.32E-02, and 0.99930, respectively.

Analysis of phase change material (PCM) melting utilizing environmentally friendly nanofluids in a double tube with spiral fins: A numerical study

Phase Change Materials (PCMs) show great potential for thermal energy storage applications due to their substantial latent heat release during the transition from solid to liquid phases. The objective of this numerical study is to assess the melting process of a phase change material (PCM) within a vertical helical coil designed as a latent heat storage system. Innovative enhancements to the system's performance are introduced through the utilization of environmentally friendly nanofluids, BH (Biogenic Hierarchical)–SiO2/water and OLE (Olive Leaf Extract)–TiO2/water, and three distinct configurations of spiral fins. A three-dimensional model is implemented to investigate the impact of the number of fins, nanoparticle concentration, initial temperature and velocity of the Heat Transfer Fluid (HTF), as well as various fin thicknesses. The porous enthalpy method within ANSYS-Fluent is employed to model the phase-changing process. The results indicate a significant reduction of 66.88 % in the melting time of solid PCM with the inclusion of three spiral fins compared to the configuration without fins. Furthermore, the thermal performance of BH–SiO2 is found to surpass that of OLE–TiO2, attributed to its higher thermal conductivity. Additionally, the analysis reveals that the melting time is more sensitive to the initial temperature of the HTF than its velocity.

Implementing Machine Learning approaches for accelerated prediction of bone strain in acetabulum of a hip joint

The Finite Element (FE) methods for biomechanical analysis involving implant design and subject parameters for musculoskeletal applications are extensively reported in literature. Such an approach is manually intensive and computationally expensive with longer simulations times. Although Artificial Intelligence (AI) based approaches are implemented to a limited extent in biomechanics, such approaches to predict bone strain in acetabulum of a hip joint, are hardly explored. In this context, the primary objective of this paper is to evaluate machine learning (ML) models in tandem with high-fidelity FEA data for the accelerated prediction of the biomechanical response in the acetabulum of the human hip joint, during the walking gait. The parameters used in the FEA study included the subject weight, number and distribution of fins on the periphery of the acetabular shell, bone condition and phases of the gait cycle. The biomechanical response has also been evaluated using three different acetabular liners, including pre-clinically validated HDPE-20% HA-20% Al2O3, highly-crosslinked ultrahigh molecular weight polyethylene (HC-UHMWPE) and ZrO2-toughened Al2O3 (ZTA). Such parametric variation in FEA analysis, involving 26 variables and a full factorial design resulted in 10,752 datasets for spatially varying bone strains. The bone condition, as opposed to subject weight, was found to play a statistically significant role in determining the strain response in the periprosthetic bone of the acetabulum. While utilising hyperparameter tuning, K-fold cross validation and statistical learning approaches, a number of ML models were trained on the FEA dataset, and the Random Forest model performed the best with a coefficient of determination (R2) value of 0.99/0.97 and Root Mean Square Error (RMSE) of 0.02/0.01 on the training/test dataset. Taken together, this study establishes the potential of ML approach as a fast surrogate of FEA for implant biomechanics analysis, in less than a minute.

Melting process enhancement in double pipe storage with multiple latent heat storage materials and oriented fins

Combining more than one passive enhancement method can significantly improve the latent heat storage performance. This paper investigates the effect of multiple PCMs (phase change materials) used in the same storage unit as well as fins and their orientation for improving the performance of LHTES (latent heat thermal energy storage) in a double pipe storage configuration. A 2D mathematical model based on the enthalpy-porosity method is used for simulations along with finite volume techniques. Validation is conducted by comparing the numerical predictions with both numerical and experimental data available in the literature. Liquid fraction, temperature distribution, energy storage, and charging time are analyzed for the melting process considering the fin number, fin orientation, and dual-PCMs positions. Results show that adding two horizontal fins reduces the charging time by 16 %, while using dual PCM with fins reduces the charging time by 25 %. Furthermore, orientation of fins (inclination of 120°) leads to 46.5 % shorter melting time compared to the horizontally finned unit. These results help in designing of efficient and cost-effective thermal energy storage systems.

Techno-Economic Optimization of Radiator Configurations in Power Transformer Cooling

In this research, a numerical approach is created to assess the effective parameters of power transformer thermal management and, as a result, improve their cooling systems. This study analyzes the radiator’s thermal performance across several arrangements and optimizes the dimensions and configurations for varied cooling loads from a techno-economic perspective. The optimization criteria were the radiator’s height (L), fin spacing (D), and number of fins (N). Due to the great complexity of the generated models, the coupled thermo-hydraulic numerical simulations were carried out on a computer cluster. An in-house radiator test facility was constructed for the experiments in order to verify the numerical model. The simulation findings accord well with the empirically obtained values. A total of 76 radiator sets were investigated. Following that, the generated findings were used to perform an optimization analysis. Finally, the response surface method was used to establish an ideal radiator layout for the specified cooling capacity at the lowest possible cost. These findings reveal that the best cooling performance is obtained when the spacing between the fins is 50 mm. Cooling capacity per unit cost rises as radiator size decreases. The cost factor and geometric details were shown to have strong connections.

Numerical thermal performance assessment of phase change process in a PCM/foam-fins enclosure under various thermal conditions

ABSTRACT The low ability of phase change material (PCM) to transfer thermal energy has created a serious challenge for the development of latent heat storage (LHTES) units. Embedding foam with high thermal conductivity material like copper has attracted significant attention. Besides, high porosity, lightweight, and easy usage are other important benefits of copper. However, its higher cost and decreasing effective volume of PCM led to the creation of amendments in the foam design. Employment of the foam in the form of fin or foam fin has emerged as an alternative method to benefit from the advantages of porous material and overcome its defects. In this study, various LHTES units with different numbers of foam fins have been simulated numerically and compared with pure PCM and fully foam PCM enclosures. Two practical boundary conditions including constant temperature and constant heat flux were examined for the designed systems. The obtained results demonstrated that foam fins have a remarkable effect on the thermal performance enhancement of LHTES under constant temperature boundary condition. For LHTES with six foam fins, 42% and 30% reductions in melting time were achieved for both types of boundary conditions including constant temperature and heat flux, respectively. At the beginning of charging process, a significant enhancement of input heat rate was proved for LHTES with 6 foam fins and fully foam up to 112% and 155%, respectively. In addition, the foam fins method provided some free volume of PCM to permit the falling out of natural convection of molten PCM.

A numerical study on the performance of chemisorption heat pump according to various design conditions

To achieve net zero, research on waste heat recovery systems is actively underway, and interest in chemisorption heat pumps is also increasing. In a chemisorption heat pump, the performance increases as the temperature of the heat source increases. However, in order to recover a larger amount of waste heat, it is necessary to develop a system that can utilize waste heat at a lower temperature. Most existing studies on chemisorption heat pumps have been conducted on systems operated using heat sources above 65 °C, and most studies have presented system performance results at specific design points. In this study, changes in system performance according to system design were quantitatively analyzed for a system driven by a heat source at 40 °C, which is lower than the existing literature studies. A 1-D transient analysis model was developed and an analytical study was conducted. Performance analysis was conducted according to pressure drop requirement, number of tubes inside the heat exchangers and reactors, and number of fins inside the reactor, and the optimal design point for each condition was suggested. The cooling capacity, coefficient of performance, specific cooling power at the optimal design point are 1100.6 W, 0.3, 45.7 W/kg respectively.

Enhancing Ocean Thermal Energy Conversion Performance: Optimized Thermoelectric Generator-Integrated Heat Exchangers with Longitudinal Vortex Generators

The effective utilization of renewable energy has become critical to technological advancement for the energetic transition from fossil fuels to clean and sustainable sources. Ocean Thermal Energy Conversion (OTEC) technology, which generates electricity by leveraging the temperature differential between surface and deep ocean waters, enables stable power generation around the clock. In this domain, the combination of thermoelectric generators (TEGs) and heat exchangers has exhibited immense potential for ameliorating the deficiencies of conventional OTEC. This study uses finite element numerical simulation of the COMSOL5.5 software to investigate the fluid dynamics characteristics of heat exchangers with flat fins and different types of longitudinal vortex generators (LVGs) under the same number of fins. This research encompasses heat exchangers with rectangular, triangular, and trapezoidal LVGs. Concurrently, the analysis examines how the vortices generated by the LVGs influence the thermoelectric performance of the TEGs. The results demonstrate that heat exchangers integrating flat fins and LVGs can enhance the power generation efficiency of TEGs. However, the pumping power required by the LVGs constrains the thermoelectric conversion efficiency. Compared to rectangular and triangular LVGs, trapezoidal LVGs achieve a superior balance between output and pumping power. Heat exchangers utilizing trapezoidal LVGs can attain the highest TEG thermoelectric conversion efficiency with a specific seawater flow velocity. Overall, these findings provide valuable reference information for applying TEGs and heat exchangers in OTEC design.

Effect of porous fin parameters on the turbulent natural convection heat transfer in the side-heated cavity containing the internal heat source

In order to study the effect of porous fin parameters on the natural convection heat transfer in the side-heated cavity containing the internal heat source, the influence of the structural parameters of porous fins (length of porous fins l, installation position of porous fins s, Installation angle of porous fins θ) and the physical property parameters of porous fins (effective thermal conductivity Ke, Darcy number Da) on the natural convection heat transfer in the cavity was numerically analyzed by arranging a porous fin on the hot wall. The effect of the coupling effect of the structure parameters of porous fins was analyzed by the response surface method, and it was found that the coupling effect of the installation position and installation angle of porous fins had the most significant effect on the convective heat transfer in the cavity, the combination of the structural parameters of porous fins with the optimal convective heat transfer effect is l = 0.053 H, s = 0.373 H, and θ = 93.21°, which increases the average Nusselt number of the hot wall by 38.72% compared with no-fin structure; The effect of Darcy number and effective thermal conductivity of porous fins on the average Nusselt number of the hot wall surface is analyzed. The results of the study can guide the study of solar radiation in buildings, the internal temperature control of automobiles, and the study of the thermal performance of electronic components.

Numerical modeling of natural convection heat transfer from radial branching heat sinks for LED cooling applications

Light Emitting Diodes (LEDs) have revolutionized the lighting industry due to their high energy efficiency. However, LEDs require effective thermal management to preserve their lifespan and luminous efficiency. In the current study, the design of a branching radial heat sink is numerically investigated and optimized for cooling LED panels of downlights under natural convection. Branching fins arranged radially on a horizontal circular plate were considered in the current study. The buoyant fluid flow over the heat sinks is observed and characterized using parameters such as fin length, height, inclination angle, and number. The dependency of Nusselt number, heat transfer coefficient and thermal resistance on the design parameters are explained by studying the buoyant fluid flow characteristics over the heat sink. Both heat transfer coefficient and thermal resistance decrease with geometric parameters such as fin length, height, and number. Due to branching, the Nusselt number decreases by 17% at lower fin lengths and by 20% at higher fin lengths, respectively. However, the thermal resistance of the heat sink arrays decreases by around 13% at lower fin lengths and remains constant at higher fin lengths due to branching. A comparative study is performed by plotting a contour map between the cooling performance of a radial branching heat sink and a radial flat plate heat sink using a heat transfer enhancement factor. Branching fins with angles above 25°and fin heights over 19 mm outperform plate-fin heat sinks of the same height and length for fin number n = 20. Finally, a correlation is proposed to predict the average Nusselt number of the fin arrays as a function of the design parameters.

Design and Optimization of Heatsink for an Active CPU Cooler using Numerical Simulations

Heat generation in CPUs with high computing performance has been a very serious issue that deteriorates their performance. To ensure that CPUs operate at their maximum potential, it is essential to maintain their temperature below 80 °C. Forced convection coolers comprising of a heatsink and fan are considered the most effective means of satisfying operating temperature requirements for a CPU in order to ensure its maximum performance. A heatsink design paired with a fan with airflow speed of 80 cubic feet per minute (CFM) for a CPU Cooler targeted at CPUs with maximum heat generation of 380 watts operating in ambient temperature of 25 °C, is developed using numerical methods of Computational Fluid Dynamics (CFD) and topology optimization using ANSYS Mechanical and ANSYS Fluent. Various fin profiles, fin arrangements, fin numbers and heatsink materials are comparatively analyzed. The best results from the comparative analyses are combined to present a base design capable of keeping the CPU temperature below 80 °C, which is the requirement for ensuring maximum computing performance. A 30 fin heatsink with covered rectangular plate fins in an arc-shaped placement configuration is determined to provide the maximum cooling performance. In materials, Silicon Carbide resulted in the lowest CPU temperature of 78°C, followed by copper at 84 °C. Silicon Carbide heatsink successfully managed to satisfy the requirements for maximum CPU performance. Copper heatsink is unlikely to cause CPU failure, but it fails to meet conditions for maximum CPU performance. In addition, this base design is then optimized for material cost reduction using topology optimization which resulted in 13% reduction in material cost with a negligible cooling performance reduction of only 0.32%. The overall design of the cooler can be improved by incorporating fan design and various CPU load conditions into the design parameters in future research.

Analysis of mixed convection and surface radiation in a horizontal channel containing different finned heat-generating blocks

In this work, mixed convection coupled with surface radiation in a ventilated horizontal channel is studied numerically. The channel containing three circular heat sources is ventilated by three openings; an inlet and two outlets. All the walls of the channel are adiabatic, and the flow enters the inlet at a cold temperature. To improve the performance of the cooling system, straight or curved fins are mounted on the surface of the hottest cylinder. The governing equations are discretized and solved using the Galerkin finite element method. The key parameters are the Reynolds number, the surface emissivity, the heat ratio and the geometric parameters of fins (size, number, and form). The numerical results show that the system's thermal performance improves by increasing the Reynolds number and the emissivity. In the absence of surface radiation (ε=0), the results indicate that adding fins leads to a decrease in the maximum temperature of the cylinder by about 6.6 °C for both straight and curved fins. However, the outcomes revealed that for ε=1, straight fins should be chosen instead of curved ones. Finally, for engineering purposes and based on the numerical data, correlations between the maximum temperature and the key parameters have been developed.

The Effects of Threshold Voltage and Number of Fins per Transistor on the TID Response of GF 12LP Technology

The Effects of Threshold Voltage and Number of Fins per Transistor on the TID Response of GF 12LP Technology

Application of performance dynamic equationin numerical simulation and optimization of waste heat utilization and storage system

In order to improve the current situation of double energy loss in waste heat recovery and utilization, according to the factors such as phase change temperature, thermal conductivity, phase change latent heat, economy, and safety of thermal storage materials, 70# phase change thermal storage balls produced by XX company were selected as phase change thermal storage materials, and differential scanning calorimetry was used to test and analyze them, and the melting point, freezing point and phase change latent heat value of PCM were obtained, provide data reference for simulation in the following text. The shell and tube heat exchanger is selected as the core component of the mobile heat storage system, and its heat storage and release processes are simulated using FLUENT software. The results show that when the heat transfer equipment is charged for 7 hours, almost all of the inner-heat exchangers have completed the heat supply, and only the phase change products at both sides and bottom of the heat supply have ?dead zone?, which is the major effect of heat storage. In order to improve the heat storage and release rate and break the ?bottleneck? of heat storage, the heat transfer was strengthened by changing the diameter size, arrangement, and adding fins of the heat exchange tube. The effects of straight fins, T-shaped fins, as well as the number, height, thickness, and width of fins on the heat storage performance were explored. The results indicate that, adding fins cannot only improve heat transfer efficiency, but also inhibit natural-convection. The heat storage and release time decreases to varying degrees with the increase of fin width, thickness, height, and the number of circumferential fins in a single heat exchange tube.

Thermodynamic optimization in laminar and fully developed flow in double pipe heat exchanger with arrow-shaped extended surfaces: A novel design

An innovative design of extended fins in the form of arrow fins is optimized for high performance heat transfer in a double pipe heat exchanger (DPHX). The arrow fins are designed within the trapezoidal fin to save material, weight, cost and making energy-efficient DPH. The arrow fins are investigated for the first time in DPHX. The FEM approach is used for computational simulation of the present work. A thermal boundary condition of constant heat flux is imposed on the arrow fins and inner pipe assembly. The results are computed in terms of fRe, Nusselt number and j-factor. The results dictate that the geometrical configurations of arrow DPHX for a significant rise in the values of the Nusselt number are: 80 % height of arrow fins is recommended when the number of arrow fins varies from 6 to 24, 20 % height for 30 arrow fins in the case of smaller values of radii ratio (Rˆ). For larger values of Rˆ, 20 % height of arrow fins may be selected for M=6&30, while for arrow fins varying from 12 to 24,H*=0.8 is recommended. On comparison of the thermal performance of the arrow-finned DPHX with the trapezoidal-finned DPHX, the maximum rise of the Nusselt number and j-factor are 113.2 % and 124.2 %, respectively. The proposed design of arrow-finned DPHX has advantages over the design of trapezoidal finned DPHX due to the significant decrease both in manufacturing cost and weight, increased thermal performance, and saving energy.

Numerical modeling for solar linear Fresnel system integrated with energy storage involving nanoparticles

To provide more secure energy, concentrated solar system can be applied in combination with thermal storage system. In current work, linear Fresnel solar system has been combined with paraffin zone. To evaluate the system, a numerical approach has been applied. Unsteady flow and heat transfer within three dimensional containers has been analyzed. Mixture of RT31 and MgO nanoparticles has been utilized in paraffin zone. Also, working fluid within the fluid zone is MgO-water nanofluid and turbulent flow has been involved via k-ε approach. According to simulation via SolTrace, the profile of absorbed heat flux was derived and considered as heat generation of outer shell. The nanofluid turbulent flows within solar systems and melting process in existence of fins have been validated according to published articles. Mesh independence procedure has been presented as well as examination for finding the best value of time step. The active parameters for current work are: Number of fins (N = 4, 16), volume ratio (V* = 0.11 to 0.24), and flow rate (Q = 2, 3 Lit/min). Adding nanoparticles can enhance the amount of T and LF about 14.28 % and 35.13 % when N = 4, Q = 2 Lit/min. As value of V* increases, the rate of process enhances although the amount of paraffin increases. When t = 120 min, with switching from Q = 3, V⁎ = 0.11 to Q = 2, V⁎ = 0.24, the values of LF and T enhance about 15.36 % and 16 %, respectively. Augment of Q leads to reduction of value of LF about 6.43 %. Increasing the number of fins can enhance the rate of charging about 6.9 %.

Numerical analysis on the thermal management of phase change material with fins for lithium-ion batteries

PurposeThe purpose of this study is to improve the thermal management of lithium-ion batteries. The phase change material (PCM) cooling does not require additional equipment to consume energy. To improve the heat dissipation capacity of batteries, fins are added in the PCM to enhance the heat transfer process.Design/methodology/approachComputational fluid dynamics method is used to study the influence of number of vertical fins and ring fins (i.e. 2, 4, 6 and 8 vertical fins, and 2, 3, 4 and 5 ring fins) and the combination of them on the cooling performance.FindingsThe battery maximum temperature can be decreased by the PCM with vertical or ring fins, and it can be further decreased by the combination of them. The PCM with eight vertical fins and five ring fins reduces the battery maximum temperature by 5.21 K. In addition, the temperature and liquid-phase distributions of the battery and PCM are affected by the design of the cooling system.Practical implicationsThis work can provide guidelines for the development of new and efficient PCM cooling systems for lithium-ion batteries.Originality/valueThe combination of PCM and fins can be used to reduce the battery maximum temperature and temperature difference.

PENGARUH GEOMETRI DAN PENAMBAHAN JUMLAH SIRIP TERHADAP DISTRIBUSI TEMPERATUR HEAT SINK SEBAGAI ALTERNATIF PENDINGINAN PADA PIRANTI ELEKTRONIK

This study aims to determine the effect of the geometry shape of the copper material heat sink fins on the surface temperature distribution of the heat sink. The material used in this research is pure copper, the shape of the heat sink fins is made rippled with the addition of the number of fins 5, 6, and 7 and the input temperature is varied from 40 C to 80 C with airflow variations from 0.2 m/s to 1 m/s. The first step is to create a heat sink design with Autodesk Inventor. Then the plan is simulated with Autodesk CFD to solve the continuity, momentum, turbulence, and energy equations. Based on the method that has been carried out, it is found that the addition of variations in the number of fins affects the decrease in surface temperature. The highest temperature drop on fin 5 ripples is 24.1 C. The heat energy transfer rate increased by 0.4657 W. The convection heat transfer coefficient increased by 3.47 W/m²C. Nusselt number shows an increase of 271. Fin performance has increased efficiency by 63.4 %, and effectiveness by 1.61. The results of this study are expected to provide practical alternatives that can be widely adopted on a heatsink plate that is very promising for future thermal developments.

Design and optimization of metal hydride reactor with phase change material using fin factor for hydrogen storage

The solid-state hydrogen storage in metal hydride (MH) is safer and energy efficient than the gaseous and liquid storage methods. The absorption of hydrogen in MH is highly exothermic. Hence, a good heat management system is required to increase the charging rate. The phase change material (PCM) can be integrated into the reactor to reuse the absorption heat for hydrogen desorption. The present numerical study models the concentric cylindrical reactor with magnesium (Mg) as MH surrounded by sodium nitrate (NaNO3) as PCM using COMSOL Multiphysics v6.1. The effect of buoyancy inside the PCM domain is investigated. An iterative approach is used to determine the required amount of PCM. Copper fins are added inside both MH and PCM. The effect of the number of fins, corresponding fin thickness and pitch on hydrogen absorption are determined to optimize the MH reactor. The outcomes reveal that the hydrogen absorption rate increases with fin numbers. The reactor with 10 and 30 fins takes 86.5 and 97.3 % less time than without fins for 90 % hydrogen absorption, respectively. The novel approach is proposed to estimate the fin efficiency (ηf) using temperature profiles of MH and fin during prevailing unsteady heat and mass transfer. The fin factor (Ff) is presented using the ηf and mass of MH. The performance evaluation criterion (PEC) is discussed based on hydrogen absorption relative to the system's weight. Further, the effect of operating parameters like hydrogen supply pressure and the initial temperature is studied on the reactor performance.

Exergetic investigation and Taguchi-based optimization of a modified passive solar still augmented with nano-PCM & fins

This study investigates the efficacy of integrating a nano-enhanced heat storage system along with fins to enhance the performance of the Double Slope Passive Solar Still (DS-SS) in the meteorological conditions of Bareilly, India (28.367°N, 79.43°E). The research approach combines experimental and statistical methods to validate the effectiveness of this system. Furthermore, an exergy-based analysis is conducted to identify potential sources of exergy losses in the system. To design the experiments efficiently, a Taguchi-based L9 orthogonal array is developed using MINITAB software, wherein three key factors are considered as control parameters: the concentration of nano particles, the number of fins, and the water-depth in the basin. The analysis of the signal-to-noise ratio, ANOVA and regression analysis indicate that the concentration of nano-particles emerges as a critical parameter, exerting 74.29% contribution in improving the yield of the heat augmented DS-SS. Modified solar still (M-SS) reflected the highest gain of 86.4%, 41.18%, and 59.54% in daily accumulated yield, ηth and ηEx respectively over the conventional solar still (C-SS). M-SS demonstrated remarkable improvements in exergy flow rates and heat transfer coefficients for convection, showing a substantial daily average gain of 109.46% and 35.64%, respectively. Additionally, it exhibited impressive results in the context of evaporation, with gains of 136.97% in exergy flow rates and 37.27% in heat transfer coefficients. Enhanced sustainability index and low waste exergy ratio makes M-SS more environment friendly. In trial 9, during adverse meteorological conditions, the heat storage capability of M-SS was evident. It showed a 1.05% times higher SI and a 4.89% lower IP compared to C-SS. The cost analysis of M-SS is also in close agreement to the C-SS.