Fin Design Research Articles

Impact of innovative fin design on phase change material melting for thermal energy storage system

Among the main types of thermal energy storage, Latent Heat Storage System has the advantage of storing heat due to the small size temperature changes and the high stored energy. These benefits are attributed to the use of phase change material. However, the most fantastic drawback of phase change material is its low thermal conductivity. To further improve the weak thermal conductivity of phase change materials in these systems, it is imperative to look at different thermal enhancement techniques. This paper discusses two primary thermal improvement approaches for a rectangular thermal energy storage system: fins and a metal matrix. The rectangular enclosure is filled with n-eicosane and the bottom surface is subjected to constant heat flux. A comparison of different structures (conventional fin, Y-shaped fin, and honeycomb structure) with a reference configuration that contains only pure phase change material was discussed. The comparison between these structures is based on the charging time, which is one of the main objectives of this work. Outcomes reveal that adding a hexagonal Y-shaped fin and honeycomb structure can help improve the thermal performance of the latent heat thermal energy storage system and uniformize the temperature compared to the reference configuration. However, the effect of natural convection is not significant for the honeycomb structure but is crucial for the reference configuration. An optimization study was done to study the effect of varying the number of the hexagonal Y-shaped fin, PCM types, and heat flux. Results show that deploying four Y-shaped hexagonal fins is the best convincing argument in favor of improving the performance of the latent storage system. The RT44HC is the predominant coolant at lower heat fluxes, whereas the RT28HC was the best choice at higher heat fluxes. These results could be beneficial in applying phase change material to the thermal management of electronic components.

Multi-objective optimization of fin shape in a cylindrical encapsulated phase change material for thermal energy storage applications

This study presents a novel fin design for a latent heat storage unit that improves its thermal performance through a methodology that integrates numerical simulation, the response surface method, and a multi-objective genetic optimization algorithm. The stored latent energy per mass (Em) and mean power (Pt) are chosen as the objectives for the optimization process. The fin parameters are optimized using the NSGA-II (non-dominated sorting genetic algorithm) to achieve the objectives of maximizing both the stored latent energy per mass (Em) and mean power (Pt). The proposed design is evaluated through simulations and the results are analyzed to determine the optimal fin configuration and the effect of the fin design parameters on the stored energy and power of the unit. The results show that the implementation of full-fin in the latent heat storage unit leads to a 7.2% reduction in total stored energy, but a 34% increase in power in comparison to the finless case. However, the use of an optimization approach results in a substantial increase in power output while maintaining minimal compromise to the stored latent energy. In particular, the optimal fin configuration, Design B, is recommended when power and stored energy are given equal importance, as it results in a 90.1% increase in power and a negligible 4.3% decrease in stored energy per mass.

Retraction Note: Optimal Design and Analysis of Airfoil Radiator Fins Based on Weakly Compressible Turbulence

Retraction Note: Optimal Design and Analysis of Airfoil Radiator Fins Based on Weakly Compressible Turbulence

A review and prospective of fin design to improve heat transfer performance of latent thermal energy storage

A review and prospective of fin design to improve heat transfer performance of latent thermal energy storage

Optimal Design of Flow Control Fins for a Small Container Ship Based on Machine Learning

In this study, the optimal design of flow control fins (FCFs) for a container ship was carried out via a machine learning approach. The conventional design practice for the FCF relied on simulation-based performance evaluation, which demands a large amount of analysis time. Instead of computational fluid dynamics (CFD)-based prediction, artificial neural network (ANN)-based prediction was attempted. Prior to the machine learning process, the wake distribution data were collected systematically via CFD. Based on the collected data, the wake distributions and resistance performance dependent on varying the fin positions were learned using the ANN, and the optimal fin position was selected with relevant optimization techniques. When multi-objective optimization was employed, it was found that both wake distributions and resistance performance were improved in a practically applicable timeframe. The current process is superior to conventional simulation-based optimization in terms of speed. From the viewpoint of prediction accuracy, in this study, ANN-based prediction was found to be equally accurate as CFD-based prediction. Thus, the results can provide a novel and reliable design methodology for the optimal design of ship appendages.

Numerical study of the thermal behavior of a cylindrical fin formed by two orthotropic media

Numerical solutions are constructed and presented for the thermal distribution, the dimensionless heat flux rate, and fin efficiency for a two-dimensional orthotropic fin of cylindrical geometry formed by two media subject to a convection limit condition on the side surface and at the high fin base, and to a uniform temperature imposed on the other base of the fin. The results are presented and discussed according to the study parameters, radial thermal conductivity ratio, radial Biot number, and axial Biot number for each medium. Many specific cases are obtained from the global solution presented in this work, among others, the temperature distribution and the dimensionless heat flux rate at the base of a single orthotropic or isotropic fin as well as the case of a fin formed by an orthotropic and isotropic media. The findings of the present study demonstrate that the newly proposed fin design significantly improves the dimensionless heat flux rate of the fin compared to the conventional design. This improvement is particularly significant when the axial Biot number of the outer medium is high and the axial Biot number of the inner medium is low, regardless of the ratio of radial thermal conductivities. These results suggest that the proposed fin design is better suited for applications where heat transfer is critical, and the external environment has a high thermal resistance. In addition, the proposed design also provides a more compact geometry, which not only improves the mechanical performance of the fin but also reduces the cost of the material used in its fabrication.

Effects of Thermodiffusion and Chemical Reaction on Magnetohydrodynamic-Radiated Unsteady Flow Past an Exponentially Accelerated Inclined Permeable Plate Embedded in a Porous Medium

A finite difference computational study is conducted to assess the influence of thermodiffusion and chemical reaction on unsteady free convective radiated magnetohydrodynamic flow past an exponentially accelerated inclined permeable plate embedded in a saturated porous medium of uniform permeability with variable temperature and concentration. The governing nondimensional set of coupled nonlinear partial differential equations with related initial and boundary conditions are solved numerically by using the accurate and efficient DuFort–Frankel’s explicit finite difference method. The physical features of fluid flow, heat, and mass transfer under the influence of the magnetic field, angle of inclination, plate acceleration, radiation, heat source/sink, thermodiffusion, chemical reaction, and time are scrutinized by plotting graphs and then discussed in detail. It was found that the effective magnetic field and angle of inclination tend to decline the fluid motion, whereas the reverse result is detected by increasing the porosity parameter and plate acceleration. The velocity and temperature of the fluid lessen with increasing the radiation parameter. The effect of thermodiffusion raises the fluid velocity and concentration, whereas a chemical reaction has the opposite impact. The Nusselt number increases with increasing the radiation parameter and time. Increasing chemical reaction and time causes to improve the Sherwood number. This kind of problem finds momentous industrial applications such as food processing, polymer production, inclined surfaces in a seepage flow, and design of fins.

Numerical and experimental investigations on melting heat transfer performance of PCM in finned cold thermal energy storage

Cold thermal energy storage (CTES) is of great importance for the enduring decrease in fossil fuel energy consumption. Moreover, CTES with phase change materials (PCMs) can be an effective measure to accumulate the heat or cooling energy for overcoming the mismatch between the supply and demand of air conditioning loads, augmenting system dependability and flexibility in operations of power grids. This paper numerically and experimentally examines the melting characteristics of PCM inside a CTES tank with the installation of interior fins. The computational fluid dynamics (CFD) software ANSYS/Fluent® is applied to predict the time sequences of liquid fraction contours and temperatures in comparison with the photographed images of ice-liquid water interface and measurement data in the CTES tank to verify the accuracy of CFD predictions. The simulations by the validated CFD model are extended to evaluate the influences of fin height and total number of longitudinal fins on the heat transfer outcomes in the storage tank. The present study further proposes a novel design adopting stratified fins to enhance the melting performance of the CTES device. The estimated mean power with the new stratified fin design is notably greater than that without fins by 156.3%, achieving the effectively liquefaction enhancement of ice for guiding the development of finned cold thermal energy storage.

Numerical investigation of turbulent nanofluid flow behavior in a multi-stream plate-fin heat exchanger with a novel design of fractal fins

Plate heat exchangers are widely used in various industries. This study considers using a novel design of fractal shape fins with a new structure on the performance of multi-stream plate-fin heat exchangers for the first time, which has not been studied by researchers before. The numerical study is done with a 3D finite volume method. The effect of using Oil/MWCNT nanofluid and using various configurations of fractal fins with different attack angles ranging from 30 degrees to 100 degrees with the range of Reynolds number of 10,000–40,000, have been studied in the current research. These changing parameters have a significant impact on the flow field and heat transfer in the heat exchanger. The results of this study show that increasing the angle of attack of fractal fins creates more flow deflection and higher fluid mixing. The rise of the Reynolds number creates stronger vortexes as the flow passes over the fins, thereby it can augment the fluid mixing in the areas which are close to the finned. As the Reynolds number rises, the growth of the thermal boundary layer diminished. It can also be seen that as the fluid impacts the fractal fins at higher angles of attack, the temperature distribution becomes more uniform in the heat exchanger. Increasing the Reynolds number from 10,000 to 40,000 increases the heat transfers up to 63 %. At the constant Reynolds numbers, increasing the fraction of solid nanoparticle volume up to 4 % in the cooling fluid augment the heat transfer rate by 48 % compared to the base fluid. Increasing the fluid velocity results the amplification of longitudinal vortex formation. Therefore, the pressure loss is higher at the increased Reynolds numbers. At the lower Reynolds numbers, the pumping power has a weaker dependency on the nanofluids concentration. Increasing the angle of attack of fractal fins increases the pumping power by 50 % compared with the angle of attack of 30 degrees. Increasing the fractal fin angle of attack compared with 30 degrees increases friction by 45–85 %. Changes in the Colburn factor show that considering all parameters that increase heat transfer, the Colburn factor increases by 23–42 % compared with the base scenario with Re = 10,000 and angle of attack = 30 degrees.

STUDI KASUS KONDISI RADIATOR PADA PERFORMA MESIN SISTEM PENDINGIN MELALUI KOMPUTASI DINAMIK FLUIDA DI PLTD BATAKAN

Computational fluid dynamics (KDF) is a commonly used method to solve physics cases that have the advantage of reducing operating costs, especially in the study of cooling systems in engines. In this study, the engine cooling system observed was located at the Diesel Power Plant (PLTD), Batakan. The cooling system on the engine has several important components that affect performance, one of which is the radiator. The condition of the radiator is observed with different fin designs, namely ideal conditions with fins (100%), 75%, and 50%. KDF helps to provide a detailed analysis of the performance of the engine cooling system. Under ideal conditions, the value of the temperature difference between the inlet and outlet in high temperature (HT) and low temperature (LT) pipes is 220C. From this study gave results, the condition of the radiator fins that were not ideal resulted in a decrease in temperature difference between the inlet and outlet in the HT and LT pipes.

Experimental and numerical investigation of melting and solidification enhancement using Fibonacci-inspired fins in a latent thermal energy storage unit

The major challenge with phase change materials (PCMs) is their low thermal conductivity, eventuating long melting (charging) and solidification (discharging) times in latent thermal energy storage (LTES) units. Using extended surfaces (fins) is a popular method to resulve this issue, with recent developments in novel designs such as tree-like and fractal fins. The complex fin configurations improve the conduction while decreasing the natural convection effects by introducing additional shear stress to the melted PCM. The current work proposes a new fin design based on the Fibonacci sequence in a vertical LTES unit to improve the charging/discharging characteristic. The finned geometry is manufactured out of a solid block of aluminum using the wire-cutting technique. Based on the volume expansion method, an experimental setup is designed to observe the charging/discharging behavior. The PCM under study is RT42 and its density, volumetric thermal expansion coefficient and solid-state thermal conductivity are measured in house. Water is the chosen heat transfer fluid (HTF) set to a constant mass flow rate of about 99 kg/h and 96 kg/h for the melting and solidification processes, respectively. The water charging temperature is 61.5 °C while the water discharge temperature is 21.5 °C. A numerical model based on the enthalpy-porosity method is implemented to investigate the physics behind melting/solidification. A careful investigation of the mushy zone constant is performed based on comparing the experimental and numerical results for melting and solidification. The average liquid PCM velocity on the melt front is studied to evaluate the natural convection behavior. The effects of secondary flows and mixing on the melting process in the new geometry are studied by investigating the liquid PCM flow behavior during the charging. The proposed fin performed 20% better in total melting time than longitudinal fins by introducing more dispersed natural convection dominated regions. The reduction of 45% in solidification time is also established for the novel fin.

Geometric optimization of pin fins for enhanced cooling in a microchannel heat sink

Microchannel heat sinks (MCHS) are widely used for active cooling of electronics. Considerable enhancements in thermal performance are achievable by finning the MCHS to extend heat transfer area and create local flow turbulence. Yet, the literature lacks multi-objective geometric optimizations of the fin design. This study optimizes the geometry of tapered squared cross-section pin-fins in a square base MCHS, where the fins’ dimensions are manipulated in terms of their area, clearance, tapering width, and tapering height ratios (AR, CR, TWR, and THR, respectively). The optimization is based on an experimentally validated computational model. The performance is analyzed for 256 finned MCHS configurations, compared with a reference unfinned MCHS. The results show a high dependency of thermal performance on AR and THR, where the hydraulic performance is more affected by AR. The executed genetic optimization procedure demonstrated non-dominated designs with thermal resistances ranging between 0.00078 and 0.0033 K/W and pressure losses ranging between 0.229 and 2.64 kPa. By considering these two performance metrics to be equally important, a balanced design with AR, CR, TWR, and THR of 0.284, 5.52 × 10−5, 0.6, and 1.0 was identified, which brings down the thermal resistance and pressure losses to only 0.000983 K/W and 0.7133 kPa, respectively.

Steady state thermal analysis of a porous fin with radially outwards fluid flow

Fins are used ubiquitously in engineering devices and systems for enhancement of heat transfer and energy storage. While traditional fins are made of non-porous materials, porous fins with natural convection porous flow orthogonal to the fin direction have also been studied. In contrast to these, there is a lack of work on porous fins in which the fluid flow may be along the direction of the fin. In such a fin, porosity may increase advective heat removal due to increased flow rate but may also impede conductive heat removal due to reduction in effective thermal conductivity. Due to these competing trade-offs, there is a need for comprehensive analysis of thermal performance of such a porous fin. This work derives a solution for the steady-state temperature distribution in a porous fin with advection along the fin direction. It is shown that temperature distribution in such a porous fin is governed by a convection-diffusion-reaction equation. A solution for the temperature distribution is derived in the form of modified Bessel functions of non-zero order. Two distinct fin performance parameters are defined and derived in order to characterize porous fin performance. It is found that thermal properties of the fin as well as ambient convective conditions strongly impact the relationship between fin porosity and fin performance. While in some cases, it is found that an optimum porosity exists that maximizes heat removal, in other cases, the use of a porous fin is found to be not desirable at all. The analysis presented here helps fully understand these trade-offs, and provides useful guidelines for porous fin design for maximum heat removal.

Effect of fin width ratio on thermal performance of fin based-heat sink with phase change materials

The rapid development of electronics, coupled with need of miniaturization in the design and manufacture, makes heat dissipation, which is critical for the performance, lifetime, and reliability of the components extremely challenging. To achieve higher heat dissipation rates, novel fin geometry with variable cross-section considering melting behaviour in medium is presented for PCM-based heat sink beyond previous efforts in literature. In this experimental study, effect of different variable cross-section, which refer different fin width ratio (s = 1, 0.5, 0.2 and 0) values are performed on the thermal performance of plate fin-based heat sink with PCM to enhance melting heat transfer. Decreasing fin width ratios point out increasing heat transfer surface area downwardly. N-eicosane is used. The constant input power is provided at the heat sink base. Thermal performance of novel fin design is evaluated by time-dependent temperature distributions, solid–liquid interface tracking photographs, reliable operating time, enhancement ratio, and thermal conductance. The results reveal that the proposed plate-fin geometry has a significant effect on the cooling performance of PCM-based heat sink. With the decrease of fin width ratio, higher temperature profile with more uniformity of 52% in the PCM medium, and so lower temperature distribution of 4.5% on the heat sink base are provided. Reliable operating time and thermal conductance values go up 15 % and 38%, respectively, for proposed fin geometry. The improvement on the thermal performance is achieved by the form of the plate-fin, which has increased surface area downward. This provides a great contribution to the conduction and convection heat transfer mechanisms at the lower half of the enclosure. Further, in this study, nearly the same reliable operating time is figured out with proposed fin geometry and fin number of s = 0 compared to higher fin number installation of s = 1 previously reported.

Study on melting and solidification performances improvement of phase change material using novel branch fin structure

A novel fin structure was proposed to improve the heat transfer characteristics of triple-tube latent heat storage system (TTLHSS). Ansys Fluent software is used for two-dimensional numerical calculation, and the model adopts melting/solidification model. The innovation of this paper is to develop a new type of fin that can simultaneously improve the solidification and melting process of PCM and optimize the structure of the new fin so that it can significantly shorten the time required to complete a heat storage and release cycle. Initially, the melting process of the case without fins and the case with new fins were compared. It was observed that compared with the case without fins, the melting and solidification time was shortened by 67.7 % and 74.8 %, respectively. Then the effects of the thickness, the length ratio, and the angle of the new fins on the melting and solidification process of PCM were studied. The liquid fraction contour of PCM in different cases and the liquid fraction curve of PCM with time were analyzed. The results show that the addition of new fins can significantly improve the heat storage and release rate of PCM in TTLHSS. Compared with rectangular fins, melting time and solidification time are reduced by 32.7 % and 52.9 % respectively. The new fins distribute the fin volume in the central area of the PCM which is difficult to melt, which improves the melting and solidification speed of the PCM and makes the overall rate more uniform. Finally, the geometric parameters of the fins are optimized by the response surface method (RSM), and the fin configuration with the cross fin thickness of 0.8 mm, the fin length ratio of 1, and the fin angle of 63.1° is optimal for shortening the total time. At this time, the time required to complete a heat storage and release cycle is reduced by 84.5 % compared with the case without adding fins. The corresponding regression equation is also obtained, which provides a basis for the design of fins.

CFD analysis of different finned tube heat exchanger designs using a non newtonian fluid

CFD analysis of different finned tube heat exchanger designs using a non newtonian fluid

Deep convolutional surrogates and freedom in thermal design

A deep learning approach is presented for heat transfer and pressure drop prediction of complex fin geometries generated using composite Bézier curves. Thermal design process includes iterative high fidelity simulation which is complex, computationally expensive, and time-consuming. With the advancement in machine learning algorithms as well as Graphics Processing Units (GPUs), parallel processing architecture of GPUs can be used to accelerate thermo-fluid simulation. In this study, Convolutional Neural Networks (CNNs) are used to predict results of Computational Fluid Dynamics (CFD) directly from topologies saved as images. A design space with a single fin as well as multiple morphable fins are studied. A comparison of Xception network and regular CNN is presented for the case with a single fin design. Results show that high accuracy in prediction is observed for single fin design particularly using Xception network. Xception network provides 98 percent accuracy in heat transfer and pressure drop prediction of the single fin design. Increasing the design freedom to multiple fins increases the error in prediction. This error, however, remains within three percent of the ground truth values which is valuable for design purpose. The presented predictive model can be used for innovative BREP-based fin design optimization in compact and high efficiency heat exchangers.

Thermal performance analysis of a new type of branch-fin enhanced battery thermal management PCM module

To solve the problem of the lightweight design of metal fins and strengthen the heat transfer between phase change material (PCM) and lithium batteries, the synergistic design of fins and phase change material-battery thermal management system (PCM-BTMS) is particularly important. In this paper, 9 new branch fin design schemes were proposed based on the conventional straight fin. The reliability of the computational fluid dynamics model was verified through the heat transfer experiments at different discharge rates. Firstly, the thermal performances of 9 new fins and the conventional straight fin under 5C discharge rate were compared and analyzed, and the optimal model was selected. Secondly, the effects of transverse fin coverage area, number, arc length, thickness, and arc length of inner and outer arc fins on the thermal performance were analyzed considering the effects of different heat transfer coefficients. The results show that the preferred fins have less effect on the heat transfer coefficient enhanced thermal performance compared with the conventional fins; the average cell temperature is reduced by 3.14 K and 3.92 K respectively by increasing the fin coverage area and the number of transverse fins to increase the contact area with PCM to enhance heat dissipation; the average cell temperature changes more significantly with the inner arc fins, and the cell temperature of Case H6 was reduced by 7.2 K; while the transverse fin arc length extension reduced the thermal performance of the system in high temperature cases. The volume of system remained the same, and the thickness of the transverse fins decreased the heat storage capacity of the system when the thickness of the transverse fins was larger. The optimal fins could keep the average cell temperature within 318.15 K. The heat transfer capability was improved by 14.98%, the operating time was extended by 131.5%, and the system weight was reduced by 10.28%.

Heat transfer augmentation of natural convection heat sink through notched fin design

A novel notched fin heat sink with a central opening is proposed in the present study to augment the heat transfer performance of the natural convection heat sink under horizontal configuration. Thermal and airflow behavior in the heat sinks were studied using both experimental and numerical methods. The results showed that the performance of the conventional heat sink can be enhanced by optimizing its fin design. The basic heat sink model provided a 17% reduction in thermal resistance when its fin height and fin spacing were doubled, and it was accompanied by a 21% increase in surface area. The heat sink with a notched fin design with a less surface area offered a 13% lower thermal resistance compared to the basic model by entraining more airflow into the interior fin region. Providing a central opening in the notched fin heat sink can further reduce the thermal resistance by about 13%. This study also analyzed the influence of emissivity of the heat sink on natural convection conditions. The findings demonstrated that the heat sink with an emissivity of 0.9 can reduce the thermal resistance by nearly 23% compared to one with an emissivity of 0.15.

A review on nanofluids coupled with extended surfaces for heat transfer enhancement

Recently, due to the increasing demands for effective and efficient devices, the thermal sections of modern machinery deserve considerable attention. Researchers in the field of thermal engineering have since devised strategies of combined passive methods for further heat transfer enhancement. From the available literature, the employment of nanofluids, coupled with extended surfaces is scarce, with limited studies optimizing both techniques. The current investigation summarizes the combined effects of nanofluids coupled with various types of extended surfaces, within numerous applications. Parameters involving the nanofluid type, volume concentration, fin geometry, and flow conditions were examined, whereby their respective effects were investigated on the thermal performances. It was deduced that the effects of surfactants, nanoparticle volume concentration, and Reynolds number significantly contributed to the heat transfer enhancement. The review presents a trend finding that nanoparticle volume concentration would positively contribute to heat transfer enhancement, up to an extent. Surpassing the optimal concentration would lead to lower Brownian motions associated with higher viscosity and density. In terms of extended surfaces, the state-of-the-art review denoted that each fin design possesses a unique attribute that alters the thermal and hydraulic performances. Nevertheless, researchers fabricating novel fin designs should highly prioritize the effects on pressure drop when employing fins. Combining both techniques, the nanofluids and extended surfaces achieved remarkable results. The outstanding results could potentially achieve the standards of active methods, for a fraction of the operational cost. Concluding, the information surrounding the present review may be of aid to researchers developing new approaches utilizing nanofluids and extended surfaces.