Fin Dimensions Research Articles

Effect of Fin Configuration on the Early Stage of the Melting Process of a Phase Change Material

Thermal storage systems are essential for optimizing energy resource utilization, particularly in the current context where sustainability and efficiency are critical. Phase Change materials (PCMs) offer a promising solution for improving thermal management efficiency without additional power consumption. Considering that the low thermal conductivity of phase change materials (PCMs) is a limiting factor for heat transfer, this study employs the enthalpy-porosity method to analyze the melting characteristics of a high-Prandtl number PCM. Additionally, this study investigated the effect of varying the number of fins in the heat sink on the heat transfer rate. The material melting process was modeled by considering buoyancy effects and treating the flow as incompressible, Newtonian, transient, and laminar. Lauric acid was selected as the working material with temperature-dependent properties that were incorporated into the simulations for greater accuracy. Three different heat sink configurations were analyzed, varying the number of fins from 5 to 10 and their lengths from 0.02 meters to 0.04 meters. The objective was to optimize the cooling performance using aluminum, which was selected for its excellent balance of lightweight properties and high thermal conductivity. This analysis aimed to assess how these variations in the fin count and dimensions affect the overall heat dissipation efficiency and thermal management of the system. The inclusion of a finned heat sink within a heat exchanger has demonstrated significant efficiency, particularly in regions with substantial boundary layer development, resulting in enhanced heat transfer. These findings highlight the effectiveness of using finned heat sinks in these regions. However, an interesting observation emerged regarding the effect of increasing the number of fins over long periods. Although initially beneficial, a larger number of fins eventually led to a reduced performance over time, notably affecting the thermal storage capacity and molten liquid mass production. Additionally, this study elucidates the influence of natural convection on thermal boundary layer development, highlighting the complexity of the heat transfer processes.

Thermal internal resistance minimisation in microchannel heat sink with perforated micro fins geometry

This study presents a 3-D numerical analysis of complex heat exchanger systems featuring innovative fin geometries. These geometries are created by modeling and placing micro fins with perforated square, circular, and rectangular designs on the heat sink. The objective of the study is to minimise thermal resistance in a hybrid heat exchanger featuring various fin architectures. The hydraulic diameter ranges from 0.036 to 0.047 mm, with fin dimensions of 0.04 mm in height and length, and 0.02 mm in width. The fins are designed with square perforations of 0.01 mm, circular perforations with a diameter of 0.015 mm, and rectangular perforations measuring 0.04, 0.012, and 0.006 mm. A high-density heat flux q″ is applied to the bottom wall, and fluid with a Reynolds number ranging from 400 to 500 is used to dissipate the heat in the cooling channel. The finite volume method and computational fluid dynamics code are employed to discretise and solve for thermal and fluid flow solutions. The impact of Reynolds number on minimised temperature and thermal resistance is analysed for void fraction ratio (VFR) of 0.25, 0.44, and 0.18.The numerical analysis reveals that the hybrid microchannel, featuring double square, circular, and rectangular perforations, demonstrates a reduction in resistance by 15 %, 21 %, and 19 %, respectively, when the coolant Reynolds number is increased by 20 %. Notably, the heat sink with square perforations exhibits the most substantial decrease in resistance, followed by circular and rectangular perforations. The numerical code is validated with what is available in the existing literature.

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

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

Maximizing liquid-cooled heat sink efficiency with advanced topology-optimized fin designs

Direct-to-chip liquid cooling offers significant advantages in managing higher power densities compared to traditional air-cooling methods. This approach utilizes nearly half the power required by server fans and air conditioners, enhances cooling efficiency in data centers. The effectiveness of this cooling strategy is intricately linked to the layout of the cold plate fins. In this research, a density-based topology optimization method is implemented in generating free-forming and non-intuitive fin structures. A pseudo-optimization model, which approximates the 3D heat sink as two 2D thermally coupled problem is selected and optimized with ‘pressure drop’ and ‘average junction temperature’ as objective function and constraint, respectively. Several fin layouts with inlet flow velocities and temperature constraints are generated. Three-dimensional numerical simulations reveal that the average junction temperature with the topology-optimized fin pattern is ∼2°C higher, and the pressure drop is significantly lower compared to size-optimized straight channel. Building on this, an inverted topology-optimized design is introduced along the channel length, inspired by the wavy nature of sectional fins. The average junction temperature with the inverted TO design is 3 to 4°C lower compared to the straight design, with a similar pumping power of 0.023 W. The TO fin layout capitalizes on frequent re-initialization of boundary layers, secondary flow-induced mixing, and the formation of Dean vortices along the channel length. Further refinement leads to the derivation of drop-oblique-trapezoidal and oval-shaped (DOTO) fins. These fins reduce average junction and wall temperatures by ∼23% compared to the inverted TO design, owing to the persistent effects of fluid dynamic phenomena along the channel length. Comparison with benchmarked designs indicates that DOTO fins reduce the average junction temperature by 3 to 6°C compared to size-optimized offset strip fins and step fins, with a similar pumping power of 0.083 W. The study indicates that optimizing DOTO fins dimensions can further enhance heat sink performance.

Innovative arrangement of circular angled fins for maximizing the discharge performance of triple-tube heat storage systems

Abstract This study introduces a novel triple-tube latent heat storage system enhanced with circular angled fins to improve solidification and heat recovery performance. The fins are arranged in staggered pattern with alternating upward and downward orientations on both sides of the PCM shell. A validated numerical model was developed using the enthalpy method to simulate the intricate heat transfer and phase change physics. Effects of circular fins geometry and operating conditions were systematically quantified on discharge rates and temperature uniformity. Four fin dimension cases (thickness × length): (2 × 5), (1 × 10), (0.66 × 15), and (0.57 × 17.5) mm2 were analyzed. The results demonstrate that fins with greater length and reduced thickness exhibit superior performance due to enhanced heat transfer capabilities, resulting in quicker solidification and faster heat retrieval. The longest 17.5-mm fins, achieving full solidification in 1973 s with 44%, 19%, and 1.9% quicker than cases with 5-mm, 10-mm, and 15-mm long fins, respectively. Incorporating an additional fin upward further reduces the solidification time by 4.5% while improving heat recovery by 3.6%. The 17.5-mm long fins increase heat discharge by 48% and outlet heat-transfer fluid temperatures by 39% versus straight fin baselines. Lower inlet heat-transfer fluid temperatures (10°C vs 20°C) reduce PCM solidification times by 31% (1755s vs 2554s) while increasing heat recovery rates by 57% (56.3 W vs 35.8 W). Overall, the integrated angled fins create a customizable latent heat storage system with greatly intensified heat transfer and thermal performance compared to conventional shell-and-tube arrangements.

Short-beaked common dolphin (Delphinus delphis) total length estimation using laser photogrammetry off the southwest coast of Ireland

Measurements from 106 stranded short‐beaked common dolphins along the Irish coast were taken between March 2017 and March 2023. Data were collected from the Irish Necropsy Project and Irish Cetacean Stranding Scheme. Total length measurements were gathered from 103 individuals where the tail flukes were still attached. These ranged between 96–238cm, mean 185.7cm, SD 31.43cm. Males (n = 58) ranged from 96–238cm, averaging 189cm, SD 34.64cm. Females (n = 40) measured 117.5–231cm, averaging 181cm, SD 25.80cm. Scaled dorsal fin photos were taken from stranded dolphins to formulate an equation to estimate the total length of live dolphins. The total lengths of 29 live common dolphins were estimated off the southwest coast of Ireland using laser photogrammetry and dorsal fin dimensions between March 2018–April 2019. Total lengths for three stranded dolphins with amputated tail flukes were also estimated. Dorsal fin base lengths were the most accurate predictor of total length R2 = 0.78. Total length estimates ranged between 143.77–242.25cm, averaging 194.78cm, SD 20.05cm. The adoption of laser photogrammetry as a measurement tool warrants further exploration as a means to reduce potential disruption from aerial systems and enhance the utility of behavioural and photo‐ID images. This study describes a non‐invasive technique with a range of possible applications for understanding pod size structure and seasonality due to this species’ approachable behaviour and inquisitive nature.

Optimization of gaseous working fluid and internally finned absorber tube for enhancing the thermal performance of parabolic trough solar collector

The current study examined the effect of various types of longitudinal finned absorber tubes with the gaseous working fluid on the performance of the parabolic trough collector. Conventional heat transfer fluids, such as water, thermal oils, molten salts, etc., have been limited when the parabolic trough collector works at very high temperatures. Gas may be used as heat transfer fluid when this collector may operate at very high temperatures. However, the heat transfer coefficient of gas is smaller than the conventional heat transfer fluid. Therefore, fins may be used to improve the parabolic trough collector's thermal performance when gas is used as heat transfer fluid. Hence, selecting the best suitable gas as heat transfer fluid and the optimum fin structure is essential to improve this collector's thermal performance. In this context, the current study has considered seven different gases, namely air, carbon dioxide, helium, nitrogen, oxygen, methane, and neon, and six longitudinal finned absorber tubes with different profiles, namely, rectangular, triangular, trapezoidal, T-shaped, and Y-shaped to select the best suitable heat transfer fluid and optimum fin structure. The best suitable gas and optimum fin profile have been chosen based on specific criteria (multi-objective optimization technique or the performance enhancement factor index). This problem has been simulated using commercial software ANSYS Fluent 2020 R2. The experimental and numerical data discovered in the literature are used to validate the results of the current investigation and found in good accuracy between them. The methane gas is found to be the most suitable heat transfer fluid based on both criteria. Then, the effect of mass flow rate and inlet temperature of methane gas on the average friction factor and Nusselt number have been investigated. It is found that the average friction factor decreases with the mass flow rate for the given inlet temperature, while the opposite trend has been observed for the average Nusselt number. For the first time, the T-shaped and Y-shaped finned absorber tube has been proposed in the present study and compared with earlier fin profiles utilized by the researcher. It is found that the increment in thermal efficiency for T-shaped and Y-shaped finned absorber tubes with methane gas is 8.9338 % and 10.1360 %, respectively. In contrast, the increment in exergy efficiency for T-shaped and Y-shaped finned absorber tubes is 8.942 % and 11.622 %, respectively. There is a significant improvement in the thermal and exergy efficiency of the proposed model compared to the models considered in the literature (air flow through absorber tube with the rectangular fin profile). Furthermore, the highest average Nusselt number of 480.4651 is found for the T-shaped finned absorber tube than other examined cases. However, the friction factor is also high for these fin profiles. As a result, the value of the performance enhancement factor for this fin profile is reduced, and the maximum value of the performance enhancement factor is obtained for rectangular fin profiles. Generally, increasing fin height and width increases thermal performance and pressure loss. Therefore, six different dimensions of rectangular fin have been studied and compared with smooth tubes. It is found that the optimum fin dimension of the rectangular fin is a height of 5 mm and a width of 4 mm. The present results can be utilized for designing an internally finned absorber tube to improve the collector's thermal performance with gas as heat transfer fluid.

Temperature analysis of TG FinFET on electrical, RF and distortion parameters for wireless applications

This article proposes four Triple Gate (TG) FinFET structures with variations in fin height and fin width with 22 nm gate length on SOI substrate. The four different structures are presented in terms of (fin height, fin width) such as D1(20 nm, 22 nm), D2(10 nm and 20 nm), D3(8 nm and 18 nm), and D4(6 nm and 16 nm). The objective is to investigate the effect of fin dimensions on the DC characteristics of the FinFET structures. Upon analyzing the DC characteristics, it is observed that D1 had an order of leakage current of 10−10 A, while D4 had 10−14 A. Additionally, D1 and D4 exhibited a change in subthreshold swing (SS) of 30%, with D1 having a value of 78.1 mV/decade and D4 having 60.0 mV/decade. The RF metric gate-to-gate capacitance reduced from D1 to D4 by 90%, and the threshold voltage of D4 was found to be 0.342 V. Based on these findings, D4 structure had better optimized results. Furthermore, temperature is varied on the D4 structure from 300 K to 500 K; electrical, RF, and distortion parameters were analyzed thoroughly. It is observed that the RF parameters reduced while the temperature increased, with transconductance frequency product (TFP), gain frequency product (GFP), and cut-off frequency (fT) decreasing by 92.1%, 98.5%, and 92.4%, respectively. However, the distortion parameters slightly increased with an increase in temperature. VIP2, VIP3, gm2, gm3, and IMD3 decreased, indicating that the device performance in wireless applications increases with increasing temperature. Overall, findings suggest that the D4 (6 nm and 16 nm) structure is a promising candidate for wireless applications, especially those that require high-temperature operation.

Passive Cooling Method Analysis & Optimization of PV Solar Panel Heat Sink

The development of solar photovoltaic (PV) systems in arid climates is hindered primarily by high temperatures, which adversely affect system performance and lifespan. This manuscript presents a comprehensive approach to address this challenge by developing an analytical model for predicting the temperature of PV panels under a passive cooling system specifically designed for arid environments. The analytical model takes into account the crucial relationship between solar panel temperature and its conversion efficiency. By applying Kirchhoff's and Ohm's laws for a complex circuit, the model accurately calculates the heat flux within the solar panel system, allowing for the determination of temperatures for each layer in the system. The study deduces closed-form analytical expressions that describe the temperature, output power, and conversion efficiency of the solar panel as functions of various factors, including solar irradiance, ambient temperature, emissivity, wind velocity, tilt angle, and dimensions of fins. These expressions provide valuable insights into the thermal behaviour of the system and enable the evaluation of its performance under different environmental conditions.

Heat Transfer and Performance Enhancement of Porous Split Elliptical Fins

To augment the heat transfer phenomenon, the infusion of various fin geometry over the heated plate is being investigated by various researchers. Solid fins of the porous medium can enhance the convective heat transfer, providing a higher surface area-to-volume ratio for heat transfer. In this work, the fluid flow pattern and thermodynamic analysis of porous-based split elliptical fins mounted staggered over a heated base plate is numerically studied with the Reynolds numbers in the range of 783 to 1839, which is dependent on the fin dimension. The variable parameters were dimensionless transverse offset ( TO ∗ = transverse offset / diameter ), which varied from 0 to 0.5; dimensionless longitudinal offset ( L O ∗ = longitudinal offset / diameter ), which varied from 0 to 0.25; porosity (ɸ), which varies from 0.8 to 0.92; pores per inch (PPI), which was 10; permeability ( P n ); and inertial parameter ( F ). To count the viscous and inertial effect inside the porous zone, the Forchheimer–Brinkman extended Darcy model was adopted. The associated parameters, the Nusselt number (Nu), frictional coefficient ( C f ), and performance evaluation criteria (PEC), are thoroughly analyzed over the TO ∗ and LO ∗ combination. The results of the investigation revealed that the highest value of Nu and PEC was obtained by TO ∗ = 0.5 and L O ∗ = 0 at ɸ = 0.92 , which were approximately 54% and 79% higher than the solid circular fin at Re = 1839 . Additionally, a response function based on Nu was obtained using the response surface method, and cuckoo optimization was assessed to identify the optimal Nu. The optimal Nu is established at TO ∗ = 0.4141 and L O ∗ = 0 ( ɸ = 0.92 and Re = 1839 ) and was validated with the present investigation with an accuracy of 1.20%.

Evaluation of the solidification process in a double‐tube latent heat storage unit equipped with circular fins with optimum fin spacing

AbstractIn this study, the effect of fin number and size on the solidification output of a double‐tube container filled with phase change material (PCM) was analyzed numerically. By altering the fins' dimensions, the PCM's heat transfer performance is examined and compared to finless scenarios. To attain optimal performance, multiple inline configurations are explored. In addition, the initial conditions of the heat transfer fluid (HTF), including temperature and Reynolds number, are considered in the analysis. The research results show a significant impact of longer fins with higher numbers on improving the solidification rate of PCM. The solidification rate increases by 67%, 170%, 308%, and 370% for cases with 4, 9, 15, and 19 fins, respectively, all with the same fin length and initial HTF boundary condition. The best case results in a solidification time that is 4.45 times shorter compared to other fin number and dimension scenarios. The study also found that moving from Reynolds numbers 500 to 1000 and 2000 reduced discharging times by 12.9% and 22%, respectively, and increased heat recovery rates by 14.4% and 27.9%. When the HTF entrance temperature was 10°C and 15°C, the coolant temperature showed that the entire discharging time decreased by 37.5% and 23.1% relative to the solidification time when the initial temperature was 20°C. Generally, this work highlights that increasing the length and number of fins enhances thermal efficiency and the phase change process.

A Comparative Study on a Shrouded Fin Array With and Without Its Finite Dimension in the Flow Geometry

Abstract In numerical heat transfer analysis, despite the involvement of the finite dimension in the geometries of heat-exchanging devices, these dimensions are frequently assumed to be adequately thin and hence neglected for the ease of analysis. But it may be essential to include the finite dimension of the heat transfer equipment which makes the study more realistic. There remains a dearth of literature in which the results of the fin heat transfer obtained from these considerations are compared, although existing numerical reports consider fin heat transfer—some including fin-thickness and the rest neglecting fin-thickness in the flow geometry. This acts as a motivation to examine and compare the results obtained from a study of numerical heat transfer on a shrouded vertical fin array including and neglecting fin-thickness in the flow geometry under mixed convection. From the present computations, it is noted that with the consideration of the fin-thickness, there is a possibility of an increase in axial pressure defect by around 45% indicating the requirement for higher pumping power. Again for the chosen range of parameters, overall Nusselt number increases by around 18% as compared to neglected fin-thickness that may arise due to altered heat transfer coefficient caused by higher velocity over the extended surface to accommodate finite fin dimension. Finally, pressure drop and Nusselt number are correlated with the governing parameters including fin-thickness.

Experimental study of natural heat transfer from finned heat exchanger fixed in variable shape of duct

The work was an experimental study of natural heat transfer from heated cylinders fixed in variable shape air duct, made from Pyrex glass. Two finned cylinders made from mild iron, outer diameter (12) mm, inner diameter (10) mm, rectangle fins dimensions (70*40) mm. The angle of two walls from the duct was changed to five angles α:(0°,3°,5°,10°,15°) with vertical to make converge shape. The cylinders were fixed inside the duct at top, centre and bottom. The cylinders were heated by supply variable power of constant heat flux (88,177,390 and 680) W/m2. The study was done with Rayleigh numbers (15x103 to 14x104). The heat was carried by free convection by atmosphere air. The results of experimental found for top location, the value of Nusselt number increased by 7.8% at ԛ•= 88 W/ m2 when increase the value of angle from 0° to 5°, and increased by 20% at ԛ•= 680 W/ m2 when increased the value of angle from 0° to 15°.For centre location, the value of Nusselt number increased by 25 % at ԛ•= 88 W/ m2 when increase the value of angle from 0° to 3°, and increase by 21 % at ԛ•= 680 W/ m2 when increase the value of angle from 0° to 10°.For bottom location, the value of Nusselt number increased by 35 % at ԛ•= 88 W/ m2 when increase the value of angle from 0° to 3°,and increased by 30 % at ԛ•= 680 W/ m2 when increasing the value of angle from 0° to 10°.The best location for the heat exchanger was at the bottom, and the best angle was 15°.

Numerical Study on Heat Transfer Characteristics of Dielectric Fluid Immersion Cooling with Fin Structures for Lithium-Ion Batteries

Electric vehicles (EVs) are incorporated with higher energy density batteries to improve the driving range and performance. The lithium-ion batteries with higher energy density generate a larger amount of heat which deteriorates their efficiency and operating life. The currently commercially employed cooling techniques are not able to achieve the effective thermal management of batteries with increasing energy density. Direct liquid cooling offers enhanced thermal management of battery packs at high discharging rates compared to all other cooling techniques. However, the flow distribution of coolant around the battery module needs to be maintained to achieve the superior performance of direct liquid cooling. The objective of the present work is to investigate the heat transfer characteristics of the lithium-ion battery pack with dielectric fluid immersion cooling for different fin structures. The base structure without fins, circular, rectangular and triangular fin structures are compared for heat transfer characteristics of maximum temperature, temperature difference, average temperature, Nusselt number, pressure drop and performance evaluation criteria (PEC). Furthermore, the heat transfer characteristics are evaluated for various fin dimensions of the best fin structure. The heat transfer characteristics of the battery pack with dielectric fluid immersion cooling according to considered fin structures and dimensions are simulated using ANSYS Fluent commercial code. The results reveal that the symmetrical temperature distribution and temperature uniformity of the battery pack are achieved in the case of all fin structures. The maximum temperature of the battery pack is lower by 2.41%, 2.57% and 4.45% for circular, rectangular, and triangular fin structures, respectively, compared to the base structure. The triangular fin structure shows higher values of Nusselt number and pressure drop with a maximum value of PEC compared to other fin structures. The triangular fin structure is the best fin structure with optimum heat transfer characteristics of the battery pack with dielectric fluid immersion cooling. The heat transfer characteristics of a battery pack with dielectric fluid immersion cooling are further improved for triangular fin structures with a base length -to -height ratio (A/B) of 4.304. The research outputs from the present work could be referred to as a database to commercialize the dielectric fluid immersion cooling for the efficient battery thermal management system at fast and higher charging/discharging rates.

Optimum orthogonally structured fins in charging enhancement of phase change materials (PCMs): PCMs’ thermophysical properties effects

Ameliorating energy storage and utilization efficiency is significant to achieving the goal of carbon peak and carbon neutralization. The orthogonal fins have been applied to enhance the average charging rate of specific phase change material (PCM) such as paraffin wax, the optimum structure dimension has been obtained. In practical applications, there are many kinds of PCMs and their thermophysical properties are different. Therefore, systematic investigations about influences of PCMs’ thermophysical properties on optimum dimensions of orthogonal fins are significant. In this work, thermophysical property effects of PCMs are numerically discussed. The mechanism is illustrated semi-quantitatively and the corresponding prediction correlations between optimum dimension of orthogonal fins and thermophysical properties of PCMs are regressed by the results. Compared to non-optimum orthogonal fins, average charging rate can be further enhanced by 20% after optimization. Thermophysical properties of PCMs significantly influence the optimum dimension of orthogonally structured fins. Higher thermal expansion coefficient, thermal conductivity, density and heat of fusion induce smaller optimum dimension, while higher viscosity and specific heat capacity induce larger optimum dimension. Meanwhile, power correlations between optimum dimension of orthogonal fins and thermal expansion coefficient, thermal conductivity, viscosity, specific heat capacity and heat of fusion are regressed. An exponential correlation between optimum dimension and density is obtained. The correlations between the optimum relative distance and the dimensionless numbers (include Stefan, Prandtl and Rayleigh numbers) are regressed from the simulations. The reliabilities of the correlations are also verified. The results supply useful information to choose and design optimum orthogonal fins to enhance average charging rate of PCMs-based LHTES unit with various thermophysical properties.

A comparative study to critically assess the designing criteria for selecting an optimal adsorption heat exchanger in cooling applications

• Adsorption heat exchanger (AdHEx) type, fin dimension and body material are studied. • Different design criteria for comparing AdHExs are employed. • Rectangular finned-flat tube and annular finned-tube AdHExs are compared. • The AdHEx superiority in terms of chiller performance and compactness is examined. • A powerful numerical tool for designing the most efficient AdHExs is provided. In an adsorption cooling system (ACS), it is essential to design the most efficient AdHEx in terms of compactness, heaviness, and ACS performance parameters. For this purpose, the coupled effects of structural type, body material, and fin geometrical specifications of its adsorber heat exchanger (AdHEx) need to be investigated. Therefore, a three-dimensional distributed-parameter model is developed and validated to conduct a comprehensive parametric study on finned flat-tube and annular finned-tube AdHExs. In this regard, two different design criteria of AdHEx heat transfer area to adsorbent mass ratio (S/m ads ) and inter-particle mass transfer resistance are adopted as common bases of the comparisons. The results indicate that for any given bed geometrical configurations, there exists a certain threshold value for the thermal conductivity of AdHEx body material. For values greater than it, the specific cooling power (SCP) and volumetric cooling power (VCP) are approximately invariant. In contrast, the coefficient of performance (COP) is mainly influenced by the volumetric heat capacity (VHC) of the AdHEx body material such that it steadily decreases by increasing VHC. Independent of body material, utilizing the smallest fin dimensions for an AdHEx leads to the highest SCPs at the cost of lowering COP, dramatically. However, maximizing VCP is more complicated because the variations of VCP with fin height show entirely distinct behaviors for different body materials and AdHEx type. It is found that estimating the superiority of an AdHEx over another is beyond the ability of common rules of thumb because of complicated transport phenomena within the adsorber beds. In light of this, the approach and results of this study properly bridge the gap between the scientific and practical aspects of designing an AdHEx based on application constraints.

CFD analysis on optimizing the annular fin parameters toward an improved storage response in a triple‐tube containment system

AbstractDue to the low thermal conductivity of the phase change material and low thermal diffusion inside the phase change material, this study seeks to improve the melting response of a triple‐tube latent heat storage system via employing annular fins by optimizing their structural parameters, including the fin number, location, and dimensions. Natural convection effects are numerically evaluated considering different numbers and the locations of the fins, including fin numbers of 4, 10, 16, 20, and 30 in a vertical system orientation. The fins are attached to the inner and outer sides of the annulus, accommodating the phase change material between the inner and center tubes. The fins' number and location are identical on both sides of the annulus, and the volume of the fins is the same across all scenarios evaluated. The results show that the higher the number of fins used, the greater the heat communication between the fins and the phase change material layers in charge, resulting in faster melting and a higher rate of heat storage. Due to the limited natural convection effect and lower heat diffusion at the heat exchanger's bottom, an additional fin is added, and its thickness is assessed. The results show that the case with equal fin thickness, that is, both original fins and the new fin, performs the best performance compared with that for the cases with an added fin with thicknesses of 0.5, 1, and 2 mm. Eliminating an extra fin from the base of the system for the case with 30 fins increases the charging time by 53.3%, and reduces the heat storage rate by 44%. The overall melting time for the case with an added fin to the bottom is 1549 s for the case with 30 fins which is 85.8%, 34.2%, 18%, and 8.8% faster than the cases with 4, 10, 16, and 20 fins, respectively. This study reveals that further attention should be given to the position and number of annular fins to optimize the melting mechanism in phase‐changing materials‐based heat storage systems.

Condensation on a Vertical Plate With Sinusoidal Microfins

Abstract A theoretically based, approximate solution for condensation on horizontal, microfinned tubes has been used as a basis to obtain a relation between heat flux and vapor-surface temperature difference for condensation on a vertical plate with sinusoidal microfins. The earlier result was in excellent agreement with experimental data with regard to magnitudes of the heat-transfer coefficient, dependence on fin and tube dimensions, and for a range of fluids with widely different properties. The new equation for condensation on a vertical plate with sinusoidal microfins takes account of the vertical gravity force and the lateral surface tension-induced pressure gradient over the curved fin surface. The equation reduces to the Nusselt result when fin height is zero and to simple area enhancement of the Nusselt result when surface tension is set to zero. Comparisons are made with experimental data for condensation of nitrogen on a vertical surface with sinusoidal microfins.

Side Fins Performance in Biomimetic Unmanned Underwater Vehicle

This paper presents the experimental research conducted for the Biomimetic Unmanned Underwater Vehicle (BUUV). The study’s major goal is to create a single, flexible side fin with adequate proportions and stiffness for an energy-efficient propulsion system. The experiments were carried out in a laboratory water tunnel equipped with a sensor for direct thrust measurement for various fin dimensions. Further, the particle image velocimetry (PIV) approach was used for a more in-depth examination of fluid–structure interaction (FSI) phenomena. The given experiments indicate the region of superior propulsion system performance and explain the main aspects that have influenced thrust generation using image processing and the PIV approach.

Numerical study on heat transfer augmentation techniques in concrete based thermal storage module for solar-thermal applications

• Thermal performance of sensible heat storage prototype is studied. • Heat transfer augmentation is investigated by varying the fin configuration. • The maximum reduction in charging time is 36.9%/. • Proposed optimized model increases the discharging rate by 75.6%. • Trapezoidal fin configuration is the best option with 50–75% cost reduction. In this study, the development and performance analysis of a concrete based thermal energy storage module with a capacity of 170 MJ operating in the temperature range of 523 K to 623 K is presented. To enhance the heat transfer rate in concrete based sensible heat thermal energy storage (SHTES) systems, the well-proven technique of fin incorporation is implemented. Longitudinal fins are attached on the outer side of the heat transfer fluid supply tube without compromising the thermal storage/discharge capacity of the storage module. Numerical simulations have been performed using COMSOL Multiphysics to study the thermal performance of the module by varying the design parameters such as the number of fins, fin dimension, and fin shape. The thermal performances of the models with fins, in terms of charging/discharging time and heat storage/retrieval rate, are compared with the model without fins for the same boundary condition. From the numerical study, it is observed that the maximum reduction in charging/discharging times of the storage module is 36.9%/48.1% and 36.9%/45.6% for rectangular and trapezoidal fin shaped models, respectively, in comparison with the model without fins. Whereas, the corresponding enhancement in heat storage/heat retrieval rate is 58.5%/92.7% and 58.5%/83.7% for rectangular and trapezoidal fin shaped models, respectively, in comparison with the model without fins. By adopting a trapezoidal shaped profile model, the fin material usage can be reduced by 50–75% without compromising on thermal performance. This numerical analysis would facilitate the design and development of efficient storage modules for solar thermal applications.