Number Of Fins Research Articles

Thermal performances of finned heat sink filled with nano-enhanced phase change materials: Design optimization and parametric study

The present numerical study proposes a novel heat sink model with combined NANO- enhanced Phase Change Materials (NANOPCM) and pin fins for the thermal management of electronic devices. The governing equations, model the heat transfer and the NANOPCM melting process, resolved by using CFD software (ANSYS Fluent) based on a finite volume method scheme. First, a comparison between heat sink with and without phase change material (PCM) was carried out. Then, different configurations of finned-heat sinks are studied to investigate the effect of 2 key parameters: the pin fin thickness and the pin fin numbers on the performance of the PCM-based heat sink. Furthermore, the effects of nanoparticles: graphene (GNP), copper oxide (CUO), and aluminium oxide (AL2O3) are investigated. The same volume fraction of nanoparticles 1.65%vol (5%wt weight fraction) was adopted to explore the most efficient NANOPCMs. Further, the impact of nanoparticle weight fractions (5%wt and 7%wt) are also detailed.This study demonstrated that the rise of pin fins volume fraction and the nanoparticles concentration don't improve the heat sink performances; the insertion of 9% pin fins volume fraction and the dispersion of 1.65 %vol graphene showed advanced performances (the operating time has been extended by 2.75 times). The results demonstrated also that the nanoparticle dispersion inside the finned heat sink does not have a significant effect on the thermal response due to the high thermal conductivity of the pin fins.

Experiment and simulation study on the specification parameters of finned heat sink for thermoelectric system in consideration of radiation among fins

Experiments and a self-built 3-D Multiphysics model are used to study the effects of the specification parameter of the finned heat sink on the heat dissipation and electrical performance of the thermoelectric system in consideration of radiation heat exchange among fins. The results show that fins number, root and tip width have certain effect on the heat dissipation capacity and the radiation simultaneously. The dissipation capacity increases the temperature difference between the hot and cold junctions, and therefore increases the electrical output of the system, while the radiation effect limits the unrestricted increase of the temperature difference, resulting in the suppression of the system performance. The system achieves optimal performance with fins number, root and tip width of 7, 4 mm and 4 mm respectively in most cases. Additionally, fin length and input temperature always devoted to facilitating the effect of the system. Two fins-optimized design schemes are proposed for thermoelectric system: the first scheme can boost the power density by 30% compared to the original one, while the second can provide an additional 50.83% of the electrical power while maintaining the original power density. This study provides a design reference for the finned heat sink for thermoelectric system.

Investigation of the optimal configuration of a highly conductive material embedded in a triangular fin

Triangular fins have gained attention for heat extraction, and various methods are suggested to optimize their performance. In this work, designing a highly conductive material (“insert”) intruding a triangular fin is investigated to increase the heat transfer from the fin, and the optimum configuration of the insert is investigated. First, the optimum design for the insert is investigated, and the triangular insert demonstrates higher heat extraction compared to a quadrilateral insert. The triangular insert resulted in a 47.7% increase in heat transfer rate compared to the quadrilateral insert. With the fixed case of = 50, = 0.1, = 0.05, and Bi = 0.05, the geometrical configuration can increase the heat flux to 64%. For the next step, the optimum design of the insert is investigated. This condition is named and which represents the results of the best case in a given situation. It is shown that geometric optimization can enhance heat removal by up to 23.8% when other parameters are fixed. Finally, the influence of different geometric and physical parameters, such as the aspect ratio of the insert, the aspect ratio of the triangular fin, thermal conductivity, and Biot number on the optimization process are investigated.

Numerical study on Phase-change thermal storage for thermal management of intermittent High-Power devices

Latent heat thermal energy storage (LHTES) is an effective approach for the thermal management of intermittent high-power output electronics. The limited heat absorption power due to the low conductivity of phase change material is an urgent problem for LHTES, besides, the thermal resistance at the coolant side also plays an important role in the heat transfer performance enhancement of LHTES. This paper investigates a finned tube heat exchanger with dual-side phase change heat transfer, i.e., LHTES of paraffin RT60 on the fin side and condensation of low-pressure water on the tube side. The proposed model couples the three-dimension enthalpy-porosity model on the fin side with the one-dimension homogeneous flow model on the tube side, yielding the solutions of the dynamic process of the LHTES. The heat-charging power and storage effectiveness of LHTES with single-phase and two-phase heat transfer fluids (HTFs) on the tube side are compared and discussed under different condensation pressures and mass flow rates. Heat transfer on both the fin and tube sides is critical for the LHTES performance, and the use of two-phase HTF on the tube side can enhance the heat-charging power by 210.5 % and raise the storage effectiveness by 33.5 %. The storage effectiveness decreases with the increase of condensation pressure while the mass flux of tube-side HTF does not have an obvious effect on the storage effectiveness. The maximum power density (1.3 kW/L) of LHTES is obtained when the condensing pressure is 90 kPa and the mass flow rate is 0.045 kg/s. It is indicated that dual-side phase change heat transfer to store energy can provide a compact and efficient thermal management solution for intermittent high-power devices. The fin density has more significant effects than fin thickness on the heat transfer at the PCM side of the heat exchanger. The average heat-charging power can be increased by 7.0 % as the fin number increases from 60 to 80.

Increasing Dip Net Mesh Size Results in More Fin Splits in Post-Smolt Atlantic Salmon (Salmo salar)

ABSTRACT Dip nets are widely used to retrieve fish from the water but can cause injuries to the fish. The objective of this study was to document the potential effects of dip net mesh size with respect to external injuries, more specifically fin splits and scale losses, in Atlantic salmon (Salmo salar). The study included 273 post-smolt Atlantic salmon from two fish batches referred to as the Tank group ( w ˉ = 178 ± 36 g, n = 198) and the Cage group ( w ˉ = 1319 ± 334 g, n = 75). Four identical dip nets with mesh sizes of 5, 10, 15, and 20 mm, respectively, were used to net fish out of their enclosures before the external injuries were assessed by visual inspection. The results showed that the number and severity of fin splits increased with dip net mesh size, but no effect of mesh size on the percentage of scale losses was found. Dip-netting of five fish at a time instead of one with the 20 mm dip net, had no statistically significant effect on the examined injuries. It is concluded that the use of dip nets with smaller mesh sizes can be positive for fish welfare by reducing fin splitting.

Study on the Enhancement of Heat Transfer Characteristics in Phase Change Process

The effect of adding fins on heat transfer rate of phase change heat storage unit was studied by numerical simulation. Different operating conditions were designed to compare the effects of the number, height and thickness of fins on enhanced heat transfer. The heat storage device is placed vertically with a 500*50*10 mm model, the inlet temperature of the thermal fluid is 373.15 K, and the flow velocity is 0.4 m/s. The optimal heat transfer rate can be determined by monitoring the liquid proportion curve over time and comparing the melting cloud image. The results show that increasing the number of fins can effectively improve the heat transfer efficiency. The 4 mm is the optimal choice for the height and thickness of the fins.

Experimental and simulation approach of cooling system in 3-phase inverter using extended surface

Overheating is a failure mode that significantly affects the reliability of electronic devices. All electronic devices, including a 3-phase inverter driving a traction motor, produce heat dissipation. Heat dissipation needs to be controlled with cooling to prevent overheating. Overheating can be avoided by increasing cooling or reducing heat dissipation. Heat dissipation in the 3-phase inverter is caused by the internal resistance of the metal–oxide–semiconductor field-effect transistor (MOSFET), switching loss, and other factors. Cooling for the 3-phase inverter can use water coolant or air coolant. The cooling system is based on the amount of heat dissipation produced. Cooling of a 3-phase inverter can use air coolant with the addition of an extended surface area in the heat sink. The heat sink uses aluminum material, often called pin fin. There are kinds of aluminum available in the market. We calculated heat generation based on the MOSFET's internal resistance, switching loss, and other factors. We validated the simulation results experimentally using a thermal camera. Thus, we could find an optimal number, dimensions, and aluminum type of fin for the cooling system in the 3-phase inverter.

Numerical investigation of curved shape fins height effect on heat transfer and flow characteristics in open microchannel heat sink

This paper explores the effect of curved shape fin heights on open microchannel heat sink performance. Different geometries of rectangular, plano-convex, and plano-concave fins have been investigated by employing three-dimensional simulation. A variety of parameters including fin height, curve range coefficient, Reynolds number, and heat flux have been examined. At the same heat flux, Reynolds number, and fin height, the Nusselt number of the rectangular fin is lower than the two shapes of plano-convex and plano-concave. In Comparison of the two curved shapes, due to their geometries and fluid flow behavior, in the lower fin heights, the Nusselt number of the plano-concave is greater than the plano-convex. In the higher fin heights, the Nusselt number of the plano-convex is greater than the plano-concave. Even though at higher fins, where the Nusselt number of the plano-convex fins is greater than the rectangular and plano-concave shape, the plano-convex pressure drop is less than these two shapes. In a heat flux of 450 kW/m2, Reynolds number of 600, and a fins equivalent height of 0.6 mm, that the volume and mass of the fins are the same, there is an 18% difference between the maximum and minimum Nusselt number of plano-convex and plano-concave, by different curve coefficients. The obtained results are beneficial in designing novel shape fins in enhanced open microchannel heat sinks.

Enhancement of the cooling by mixed convection of a CPU using a rotating heat sink: Numerical study

The technological progress made in recent years has driven electronic apparatus to become not only more efficient and work faster but also considerably smaller in weight and size. Furthermore, the power densities of these devices have known an impressive increase. However, the challenge for the electronic industry is the lifetime device improvement by controlling the adequate removal of their excess heat. The use of more efficient cooling systems is, therefore, crucial in order to ensure durable device functionality. In this work, computational simulation was carried out to study the enhancement cooling process mixed convection of an electronic component (CPU mounted in a motherboard) using a new design of a heat exchanger by combining the heat sink (the finned surface) and the fan in a single component, this allows more heat to be moved faster and with less energy than a conventional cooler. Three radial heat sinks (HS18, HS24 and HS36) are considered depending on circumferential fin numbers ( n = 18, 24 and 36). The effect of Reynolds number, heat flux and rotational velocity is investigated, and the optimum comprehensive performance was determined. The results reveal the cooling performance turns out to be better for heat sink with n = 36. The rotational velocity operates a significant effect on the temperature field only for values below than 900 rpm. We also found that the improvement in the Nusselt number and its percentage enhancement is intensified with increased rotational velocity and decreased with heat flux. A bigger Ω and ReΩ meant a more obvious heat transfer enhancement (NuΩ/Nu0) in the case of smaller Q, but (NuΩ/Nu0) decreased with increasing Q.

Multi-Parameter Optimization of Heat Dissipation Structure of Double Disk Magnetic Coupler Based on Orthogonal Experimental Design

The existing heat dissipation research on double disk magnetic couplers ignores the coupling influence of electromagnetic temperature–stress and other multiphysics fields, and the error between the calculation and analysis results and the measured values is large. Therefore, a multi-parameter optimization method for heat dissipation structures of double disk magnetic couplers based on orthogonal experimental design is proposed. Based on the double disk magnetic coupler model, a three-dimensional finite element model based on fluid–solid–heat coupling is established, with the axial air gap length, input motor speed, the thickness of the permanent magnet in the magnetizing direction, the thickness of the copper plate, the number of fins of the heat dissipation plate and the length of the fins of the heat dissipation plate as design variables. Six-factor and three-level simulation experiments are designed with the minimum temperature of the heat dissipation plate as the objective function, and additionally, orthogonal experiments were designed according to the actual working conditions by selecting the optimal combination of parameters and modifying the model to perform physical tests. The results show that the variables that have the most significant impact on heat dissipation performance from high to low are as follows: axial air gap length, input motor speed, the length of the fins of the heat dissipation plate, the thickness of the permanent magnet in the magnetizing direction, the number of fins of the heat dissipation plate and the thickness of the copper plate. The increase in axial air gap length can effectively reduce the temperature rise, and the maximum decrease can reach 9.76%. Under the same conditions, the input motor speeds are set to 300 r/min, 400 r/min, 500 r/min, 600 r/min and 700 r/min, respectively, and the simulation results are in good agreement with the physical test results, with a maximum error of 4.8%. The error between the simulation result and the physical test result is only 1.9% under the optimal combination of parameters obtained by the orthogonal experiment, which verifies the correctness of the optimization model. In conclusion, the study is of reference significance for the parameter optimization of the heat dissipation structure of the double disk magnetic coupler.

Experimental comparative analysis of close-contact and constrained melting of n-eicosane in a finned rectangular cavity

Thepresent study demonstrates and visualizes the two modes of constrained melting and close-contact melting in a rectangular cavity enhanced with fins. Three configurations of fin with different lengths and numbers are tested in different horizontal, inclined, and vertical orientations. N-eicosane is used as the phase change material, and the experiments are performed with water as the heat transfer fluid at the inlet conditions of 50 °C, 55 °C, and 60 °C. In general, the close-contact melting time is shorter by 42–50%, compared to the convection dominated constrained melting in the unenhanced cavity without fins. By using fins to enhance the process, the melting time is reduced by 49% and 35% in the constrained and the close-contact modes, respectively, compared to the unfinned cavity in each mode. The thermal performance is observed to be superior in the horizontal and the inclined orientations. In these orientations, the buoyancy-driven structures are not blocked by fins in the constrained mode. In the close-contact mode, the solid specimens attain more consistent contact with the base of the cavity and with the extended heat transfer area at the inclined and horizontal conditions. In the vertical orientation, the asymmetrical melting by the fins results in a rotational movement of the solid PCM and close-contact perturbations. The variations in the number of fins are found to have minor effects on the overall close-contact-induced melting. On the other hand, increasing the length of the fins is a more promising measure, providing consistent and prolonged contact.

Melting expedition in horizontal triplex tube heat exchangers via radial and combined radial-axial fins

The effects of using radial fins on the melting of a Phase-Change Material (PCM) inside a horizontal Triplex Tube Heat Exchanger (TTHX) are investigated in this study. To this aim, several configurations of radial fins and their combination with conventional axial fins are considered. First, the melting in a TTHX equipped with axial fins is simulated to assess the validity of the solver. The numerical predictions agree well with the experimental data. Next, the melting process in a TTHX equipped with different configurations of radial fins is simulated to compare their thermal performance with that of the longitudinal fins. Effects of multiple parameters are investigated, such as the fin radii and number, replacing full circle fins with arc fins, and axial distribution of the fins. The results indicate that inserting arc fins in the lower section of the PCM enclosure improves the thermal performance significantly. This leads to an 18 % reduction in melting time when their axial spacing is non-uniform. Also, combined radial-axial configurations, considered in the present research for the first time, greatly accelerate the melting if the axial fins are located on the inlet side of the PCM enclosure and the radial fins are located on the other half.

Investigation of morphological characteristics of concentric tube thermals energy storage.

This study focuses on the heat transfer intensification of concentric tube type thermal energy storage (TES). The collective influence of aspect ratio (ratio of length to diameter of the tube) and number of fins is investigated. To optimize thermal energy storage, first an optimal aspect ratio investigated. And then, optimal number of fins is obtained. Results are compared based on the amount of liquid fraction available after 120 minutes of charging and discharging. It was found that with an increasing aspect ratio, liquid fraction also increased, but up to the aspect ratio of 11. Afterwards, an increased aspect ratio showed insignificant change in the liquid fraction. Similarly, liquid fraction in case of charging was increased with increasing the number of fins up to 8. Afterward, an increased number of fins showed insignificant change in the liquid fraction.

Galerkin finite element analysis for buoyancy driven copper-water nanofluid flow and heat transfer through fins enclosed inside a horizontal annulus: Applications to thermal engineering

The hydrothermal significance of natural convection flow through the horizontal annulus reveal most important implication and those geometrical shapes are introduced in enormous industrial and engineering implementations related to superheaters, heat exchangers, hydrogen fuel cells, gas turbines, solar collectors, vehicle engines, and turbomachinery etc. With this motivation, the current advance study enlightens the natural convection heat transfer impacts of Cu−water nanofluid flow through horizontal annulus with inserting Fins at the inner cylinder. Different fins numbers (0, 2 and 4) are inserted at inner cylinder wall are heated. The outer cylinder kept at cooled temperature. The significance nanoparticles fraction (Φ=1%−5%), Rayleigh number (1000,10000and100000) and different fin numbers (0,2and4) on fluid flow, thermal field, and local Nusselt number investigated. The Galerkin finite element method has been employed to carry out the numerical solution for different values of flow controlling parameters. The impacts of prominent parameter on streamlines, isotherms and 2d graphs are analyzed. The analysis concluded that velocity and thermal outcomes upsurges for Rayleigh number. It is conclude that important thermal transfer increment can be observed due to the occurrence of solid nanoparticles and that is boosted by growing the solid particle fraction. The velocity is reduced by increasing the values of nanoparticle volume fraction. Additionally larger heat transfer for nanoparticles Volume fraction Φ=5% as compare to Φ=1%.

Thermal analysis of multi-finned plate employing lattice Boltzmann method based on Taylor-series/least-squares

A comprehensive experimental/numerical investigation is carried for the purpose of heat transfer and hydrodynamic analysis of natural convection within a cavity equipped with active rectangular fins. Numbers of hot and cold fins are fitted at the surface of square cavity which have remarkable effect on the hydrothermal performance of cavity. In this work, some parameters with significant impact on hydrothermal performance are selected to be studied such as value of Rayleigh number (Ra), value of nanoparticle volume concentration (φV) and arrangement of active fins (Ther.Arr A, B, C and D). To reach this purpose, numerical approach and empirical observations are coupled to provide an accurate data. In order to make the standard Lattice Boltzmann Method (LBM) compatible with the non-uniform grid distribution, the Taylor series expansion and least square-based lattice Boltzmann method (TLLBM) is used. Furthermore, firstly, the SiC-EG nanofluid samples are prepared using modern experimental, and then its rheological and thermal properties are measured using modern devices. It is concluded that using of nanofluid and the thermal arrangement of fins, have significant impact on the thermal performance of cavity.

Evaluation of phase change material melting process in an energy storage chamber with porous metal foam gradient and discrete strip fins

In this research, the process of melting the phase change material (PCM) in a thermal energy storage chamber with the discrete strip fins, metal foam gradient, spatial, and temporal changes in the wall has been investigated. The efficacy of geometric parameters, fin arrangement and fin material on the melting process has been explored. RT82 is considered as the PCM. Temporal changes in wall temperature in both step and sinusoidal modes are considered. To simulate the liquifying-freezing process, the porosity-enthalpy method base on the finite volume method is applied. The outcomes display that in various cases of the study, the result shows that the number of fins affects the melting time. The melting time for discrete fins is reduced by about 50 % compared to continuous fins. The outcomes indicate that the melting fraction rate is improved in the step mode compared to the constant temperature mode. In the sinusoidal state, the infiltration of wall temperature fluctuations into the melting fraction is observed and the melting fraction value is fixed around a value after a specific time. The spatial distribution of wall temperature influences the melting time. The parabolic temperature distribution with location provides about 42 % improvement in the melting process compared to the constant temperature state. The effects of positive and negative porosity gradients in three spatial directions on the melting process and energy storage have been explored. The porous medium and the change of its porosity coefficient are effective on the melting process and the melting time is reduced by about 90 %.

Performance enhancement for exhaust thermoelectric power generation system by using porous pin fins based on a fully automatic optimization method

An intelligent optimization method combining Non-dominated Sorting Genetic Algorithm-II (NSGA-II) algorithm and Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) decision is implemented to design the optimal arrangement of porous pin fins in the flow channel of the exhaust thermoelectric power generation (ETEG) system. This method realizes the optimal arrangement of the porous pin fins while considering the two contradictory performance indicators at the optimization level: system output power (P) and pressure drop (Pd). In this work, the design of porous and solid pin fins is first compared. Secondly, four typical pin fins arrangement models are established with preliminary analysis. Finally, the NSGA-II-TOPSIS intelligent optimization method is implemented, which takes P and Pd as objective function, the position, number and relative distance of the porous pin fins as optimization variables simultaneously. Through iterative optimization, the optimal arrangement scheme achieves a proper balance between P and Pd. The main conclusions include: The design of the porous pin fins can increase 22.89% for P of the ETEG system while reduces 82.98% for Pd. The distribution of dense downstream of porous pin fins can best improve the ETEG system performance. After optimization, higher P and lower Pd of the ETEG system are obtained with fewer pin fins. A new index is proposed to evaluate optimal solutions, the optimal design with 2 porous pin fins reaches the highest value: 5.86 W Pa−1, which means that each pin fin is fully used.

Machine Learning-Based Approach for Modeling the Nanofluid Flow in a Solar Thermal Panel in the Presence of Phase Change Materials

Considering the importance of environmental protection and renewable energy resources, particularly solar energy, the present study investigates the temperature control of a solar panel using a nanofluid (NFD) flow with eco-friendly nanoparticles (NPs) and a phase change material (PCM). The PCM was used under the solar panel, and the NFD flowed through pipes within the PCM. A number of straight fins (three fins) were exploited on the pipes, and the output flow temperature, heat transfer (HTR) coefficient, and melted PCM volume fraction were measured for different pipe diameters (D_Pipe) from 4 mm to 8 mm at various time points (from 0 to 100 min). Additionally, with the use of artificial intelligence and machine learning, the best conditions for obtaining the lowest panel temperature and the highest output NFD temperature at the lowest pressure drop have been determined. While the porosity approach was used to model the PCM melt front, a two-phase mixture was used to simulate NFD flow. It was discovered that the solar panel temperature and output temperature both increased considerably between t = 0 and t = 10 min before beginning to rise at varying rates, depending on the D_Pipe. The HTR coefficient increased over time, showing similar behavior to the panel temperature. The entire PCM melted within a short time for D_Pipes of 4 and 6 mm, while a large fraction of the PCM remained un-melted for a long time for a D_Pipe of 8 mm. An increase in D_Pipe, particularly from 4 to 6 mm, reduced the maximum and average panel temperatures, leading to a lower output flow temperature. Furthermore, the increased D_Pipe reduced the HTR coefficient, with the PCM remaining un-melted for a longer time under the panel.

Modelling of the temperature profile of heat sinks for a thermoelectric cooler module

Thermoelectric refrigeration achieves cooling through Peltier and Seebeck effect. Heat sinks attached to the hot and cold sides of the thermoelectric module help to efficiently dissipates and absorb heat. This research modelled the temperature profile across a heat sink and its optimization for a thermoelectric refrigeration application. Simulation was carried out using MATLAB to visualize the performance of the heat sink. The optimization was done using FMINCON in MATLAB by setting upper and lower bounds to satisfy space and volume requirement. The optimum values for the hot and cold heat sink geometry obtained using FMINCON tool in OPTIMTOOL box in MATLAB, yields number of fins as 10, fin spacing as 0.003m, the fin thickness as 0.002m and fin length as 0.015m with an optimum temperature of -0.8639.

Investigation on the H2 fueled combustion with CH4 and C3H8 blending in a micro tube with/without fins

Combustion characteristics and working performance of the blending hydrocarbon fuels in a micro combustor are investigated. Experiments and simulations are conducted to analyze the effects of CH4 and C3H8 blending on the premixed H2/air burning process and wall temperature distribution. To enhance the radiation power and energy conversion rate of the micro thermophotovoltaic (TPV) system, the combustors inserted with varied fins are proposed and compared. The results indicate that the premixed H2/air combustion with 7.5 % CH4 addition gains the best thermal ability due to the flame location modification and reaction zone extension. Nevertheless, the combustion with 5 % C3H8 blending achieves the highest wall temperature in C3H8/H2/air burning. Moreover, the CH4/H2/air combustion gains a better thermal performance than that of C3H8/H2/air burning under the same blending ratio owing to the descending heat loss from the outlet and enhanced reaction intensity. The reaction pathway and sensitivity analysis demonstrate that the chemical reaction rate related to the OH radical is reduced with the CH4 or C3H8 blending ratio, leading to the stretched flame. The reaction rate of CH4/H2/air combustion is higher than that of C3H8/H2/air, increasing the heat release. Besides, the inserted fins optimize the fluid field and enhance the heat recirculation, then a higher radiation temperature is obtained. The combustor with appropriate fins number and length effectively achieves a satisfactory working performance. In particular, the highest radiation efficiency of 54.0 % and highest radiation power of 69.1 W are obtained in the combustor C8-24 burning with 7.5 % CH4 under chemical energy Ec = 91.5 W and Ec = 141.4 W, respectively.