Fin Arrangement Research Articles

Efficiency improvement of ternary nanofluid within a solar photovoltaic unit combined with thermoelectric considering environmental analysis

Impacts of environmental parameters and dust deposition on the efficiency of solar panel have been scrutinized in this article. To gain thermal output, trapezoidal cooling channel has been attached in the bottom of the panel incorporating ternary nanofluid. To produce working fluid, water has been mixed with Fe3O4TiO2GO nanoparticles. Also, the arrangement of fins has been considered to grow the cooling rate of the silicon layer. The existence of a thermoelectric layer above the cooling channel leads to higher electrical output. Efficacy of ambient temperature (Ta), speed of wind (Vwind) and inlet temperature (Tin) and velocity (Vin) of ternary nanofluid on performance of PVT has been assessed. As Tin increases, electrical efficiency declines about 3.63%. Increase of ambient temperature makes thermal performance enhance about 33.46%. The PVT efficiency decreases about 13.14% and 16.6% with augment of wind speed and dust deposition. CO2 mitigation has been uced about 15.49% in presence of dust while it increases about 17.38% with growth of ambient temperature.

Enhanced thermal performance of shell and tube phase change heat accumulator with novel biomimetic spider web fins

Shell and tube phase change heat accumulator (STPCA) has many advantages such as flexible arrangement, simple structure and high operation temperature and pressure. However, there are some limitations such as the low thermal conductivity of phase change material (PCM) and much un-melted PCM at the bottom of STPCA. In this contribution, in order to solve aforementioned problems of STPCA, we firstly designed novel biomimetic spider web fins and applied the enthalpy-porosity method to solve the problem of phase transition and obtain the liquid fraction and location of the solid–liquid interface at different times. Then, we compared the enhance heat storage effect of the novel fins with that of normal radial fins. In addition, we further analyze the effects of three different fin arrangements and four different fin radial angles on the thermal storage performance. The results show that the novel biomimetic spider web fins can accelerate the melting of PCM at the bottom of the accumulator, uniform the temperature distribution and greatly improve the heat storage rate of the accumulator. The complete melting time of PCM of the accumulator with the novel web fins is only 48 s, but the radial fins is 140 s, which is much longer than that of the accumulator with the novel web fins. Moreover, the radial angle mainly affects the later melting period, because the angle can affect the natural convection. In this work, the model with a radial angle of 75° shows the better thermal storage performance. This contribution can provide a guidance for STPCA design to improve the heat storage performance.

Thermal management of lithium-ion battery pack under demanding conditions and long operating cycles using fin-enhanced PCMs/water hybrid cooling system

A fin-enhanced hybrid cooling system combining phase change material (PCM) and liquid cooling is designed and optimized in this work to ensure the stable operation of lithium-ion battery under high ambient temperature, high discharge rate or long operating cycles, which is a challenging and burning issue. The coupling effects of composite PCM, fin arrangements, cooling water inflow schemes, and ambient temperature on the heat dissipation performance of battery pack are numerically studied. The maximum temperature can be reduced by up to 7.66 °C with expanded graphite modified PCM at 5C discharge rate and 40 °C ambient temperature, and the optimal mass fraction is found to be 12–16%. The arrangement of composite fins and two-layer PCM can further improve adaptability with better temperature control or temperature uniformity, and the suitable ranges of ambient temperature, coolant inlet temperature and velocity for safe operation are obtained. In general, the hybrid cooling system with fins and counter flow can be used for the thermal management design of batteries used at high temperature of 40 °C and high discharge rate of 5C, and the temperature and temperature difference can be controlled to within 46.2 °C and 4.2 °C respectively. The hybrid cooling system also offers a reliable cooling performance during 2C rate of charging and discharging cycle process, and the temperature and temperature difference can be controlled below 42.2 °C and 1.7 °C respectively.

Large-eddy simulation of non-isothermal flow over an array of cylinders placed inside a converging channel

This work evaluates the flow and thermal characteristics of a gas-turbine blade trailing-edge. The study is carried out using large-eddy simulation (LES) for Reynolds number, Re=5900. In view of the realistic conditions, a converging channel with a staggered arrangement of fins with varying aspect ratio is considered for the higher pressure of the coolant and the larger temperature difference between the blade and the coolant. The present results are compared with the parallel channel case to identify the effects of converging flow passage of the channel on the flow and thermal characteristics. The computational setup and methodology are thoroughly validated using reference data from experiments as well as LES available in the literature. The results are analyzed in terms of Q-criterion, streamlines, vorticity and turbulent heat flux contours, and the Nusselt number profiles at several locations in the flow domain. The present results shows, unlike in the parallel channel case, a dominant spanwise component of velocity that helps in the formation of a strong vortex behind the first row itself, and the Nusselt number consistently increases from the first to the last row. The maximum gain and diffusion of turbulent heat flux occur within a recirculation zone and along the free-shear layer, respectively. The heat flux from the end-wall is extracted mainly by the spanwise velocity component, which is also responsible for its advection to the central region. Heat transfer is observed to be higher from fins compared to the end-walls, which underscores the importance of the active participation of fins in the analysis of heat transfer at the trailing-edge.

Leaf-vein bionic fin configurations for enhanced thermal energy storage performance of phase change materials in smart heating and cooling systems

In the present study, we investigated the effect of different structures of a novel leaf vein bionic fin and various arrangements in the tube on the complete melting time of phase change materials (PCM) in a triplex-tube thermal energy storage (TES) system. RT82 was adopted as the phase change material. The enthalpy-porosity method was employed for this numerical study. The numerical model was validated against experimental data from a previous reference. The simulation results demonstrate that the novel fins deliver significant reductions in the duration of complete melting. Based on fin-branched vein numbers of 1, 2 and 3, increasing the fin angle from 30° to 60° can reduce the complete melting time by up to 14.3%. Additionally, adjusting the fin arrangement can save up to 6.35% of the complete melting time. The proper arrangement of the fins can improve the heat transfer performance of the PCM. The non-dimensional quantities analysis of the calculated results shows that the melting time is negatively correlated with the non-dimensional angle. As the non-dimensional parameter, fin arrangement number decreases from 1, the complete melting time corresponding to the fins of different structures first decreases and then increases for the phase change material.

Coupled Electrical–Thermal–Fluidic Multi-Physics Analysis of Through Silicon Via Pin Fin Microchannel in the Three-Dimensional Integrated Circuit

Abstract To solve the thermal management problem in the three-dimensional integrated circuit (3D-IC) with high integration and multilayer, this paper establishes a 3D-IC interlayer microchannel model with various embedded TSV micropin fins to explore the temperature distribution of chips and the flow velocity distribution inside the microchannel. The paper selects the sense amplifier and the half adder as the heat source of the memory and processor in the calculation model. The power densities of the sense amplifier and the half adder are 885 kW/m2 and 1.832 MW/m2 combined with the layout size, respectively. Meanwhile, the effects of the shape and arrangement of TSV micropin fins on the flow and heat transfer characteristics are investigated. The result shows that the 1.2:1 diamond micropin fin microchannel with staggered arrangement has the best overall flow and heat transfer performance. Compared with the basic circular micropin fin with the in-line arrangement, the average Nusselt number of this microchannel is improved by 3.20–3.37 times, and the maximum temperature of chips is controlled at 325.92–312.43 K for Re = 628–1819.

A Comprehensive Review and Experimental Investigation on Heat Pipes Application in Electrical Machines

The rapid development of transportation electrification brings unprecedented opportunities and challenges as well to the technological improvement of high-power density motors. As the major restriction of the motor performance, thermal issues attract more attentions recently and the heat pipe (HP), due to its high thermal conductivity and lightweight characteristics, is identified as a promising solution. Though HPs have been attempted in cooling systems of electrical machines, their thermal benefits still need to be fully understood. This article provides a comprehensive review and performs a series of experimental investigations to fill the technology gaps for the HP application in electrical machines. Firstly, the HP technology is briefly introduced, followed by a detailed review on its applications in different locations of electrical machines with corresponding thermal improvements reported. Then, experimental tests are conducted to investigate the correlation between the HPs’ parameters and their cooling effectiveness, including cross-sectional shape, bending angle, fins arrangement and inclination angle. The obtained results and conclusions could provide a guideline for the promotion of HPs in next generation electrical machines for future transportation.

Performance evaluation of nano refrigerant operated thermosyphon using artificial neural network technique

The present work is focused on evaluating the performance of a thermosyphon with internal fin and internal cut arrangement employing a mixture of nano particle Al2O3 and refrigerant R134a using artificial neural network. Using feed forward back propagation algorithm technique has used the data from the experimental studies to predict the thermosyphon performance. The input parameters to the algorithm were heat input, heat flux and cooling water temperatures and the output parameter predicted by the algorithm is heat transfer coefficient. It was inferred from the analysis that the predicted values of heat transfer coefficient were close to the actual experimental data. The artificial neural network model predicted the values in close agreement with the experimental values with an error of ±3%.

Effect of novel concentric annular fins on the melting and solidification process of stearic acid in thermal energy storage devices

The latent heat thermal energy storage device provides an alternative solution to the problem of imbalance between energy supply and demand. To enhance heat transfer, a series of latent heat thermal energy storage devices with novel concentric annular fins are proposed, as the design accelerates the melting and solidification processes of stearic acid. Based on the finite volume method, the enthalpy-porosity approach is employed to numerical simulation the charging/discharging process. Effects of the number and arrangement of concentric annular fins on the liquid fraction, melting and solidification front, melting uniformity, temperature uniformity, velocity uniformity and total melting and solidification time during melting and solidification are studied. Results showed that the melting and solidification rate increases with increasing fin number. The total melting and solidification times were reduced by 72.83% and 86.39%, respectively, for the case with 9 concentric annular fins compared to the bare tube. Both melting performance and temperature uniformity were improved. Further, the effect of fin arrangement on the melting and solidification performance was investigated with the same total volume of fins. Results revealed that the heat transfer performance of progressively shorter fin structures < uniformly distributed fins < progressively longer fins < performance of non-uniformly distributed fin arrangement. The non-uniform fin arrangement reduces the total melting and solidification time of stearic acid by 85.46% and 90.11%, respectively, compared to bare tube. This work provides new insights into the understandings of the transient phase change process and the strategies for guiding the design for thermal energy storage devices using annular fins.

Cesaro fins parametric optimization for enhancement in the solidification performance of a latent heat storage system with combined fins, foam, and nanoparticle

The use of Phase Change Materials (PCMs) for latent thermal energy storage enhances the availability of solar energy. PCMs can store a large amount of energy in a small volume using almost entirely isothermal processes. Despite this, the poor thermal conductivity of PCMs is a significant disadvantage of current PCMs, severely limiting their energy storage capabilities. As a result, the solidification/melting rates are reduced to an unacceptable level, and the system reaction time is increased unreasonably. By combining the novel fin arrangement, nanoparticles, and metal foam, the current study improved the solidification rate of the PCM in the Latent Heat Thermal Energy Storage System (LHTESS). LHTESS was numerically evaluated in ANSYS Fluent 18.1 using a solidification and melting model. The addition of cesaro fins, nanoparticles, and metal foam significantly improved PCM solidification in the LHTESS. PCM solidification time was reduced by 42.42% and 39.39% in Type-3 and Type-5 fin configurations, respectively, when compared to Type-4 fin configuration. Furthermore, a temperature difference of 27 K between the Heat Thermal Fluid (HTF) and the PCM ensures the best solidification performance. By incorporating nanoparticles into PCM and metal foam, the solidification time is reduced by 73.68%. Depending on the foam structure and volume fraction of the nanoparticles, dispersing nanoparticles in PCM with metal foam saves up to 75% of the time.

Solidification of nanoparticle-based PCM in a fin-aided triplex-tube energy storage system for cooling applications

Accomplishing a better solidification rate to enhance the Thermal Energy Storage (TES) systems' performance is crucial. One such storage system is the Triplex-tube heat exchanger (TTHX), which is preferable due to its larger heat exchanger area that makes the phase change rate faster. The present study demonstrates a combination of different heat transfer enhancement techniques to improve the performance of the TTHX system. The heat transfer performance of the entire solidification process in the heat exchanger is numerically studied. The system is designed for low-temperature cooling applications with water as PCM placed in between the annulus region of the TTHX. Fins have been employed to enhance the low heat transfer rate due to the poor thermal conductivity of the water as PCM. The effect of incorporating maximum fin length between the annulus region on the discharging performance is evaluated. In this regard, two fin arrangements – attached and detached are investigated. The influence of different cooling methods, namely both-side, inside and outside, are evaluated for mentioned fin arrangements in terms of the required solidification time, liquid–solid interfaces, and heat transfer rate. The impact of including CuO nanoparticles on the thermal and flow structure under different volume fractions is investigated. The results demonstrate that detached fins perform superior under a given heat transfer fluid temperature among other fin cases. In comparison, both-side cooling expedites the process better than other cooling methods. Inclusion of 7% nanoparticles along with fins results in an even faster freezing process, which helps to reduce full solidification time in all cases by nearly 29% and 25% in attached and detached fins, respectively.

Energy storage analysis during melting in presence of metallic fins via numerical method

The performance of the storage unit during the discharging process can be improved with installing extended surfaces and this study aims to show the effect of two arrangements of fins on solidification. The same area of I and V shaped fins indicates that the volume of paraffin will not change with altering the configuration of the system. Unsteady terms were applied via implicit technique and two dimensional domains were simulated via FVM to show the behavior of the system during discharging. The conductivity of utilized paraffin (RT28) has been improved by loading nanoparticles of CuO. Since the fraction of additives is low, it is logical to use homogeneous model formulation to derive the properties of NEPCM. The both cases were compared and outputs showed that the required time for case 1 is 8.93 % lower than that of case 2. With involving I and V shaped fins, the required time of freezing will be 47.26 min and 51.89 min, respectively.

Investigation on the thermal management performance of a non-contact flow boiling cooling system for prismatic batteries

It is a great challenge to control the temperature of high energy-density lithium-ion batteries within an appropriate working range during rapid charging and discharging with a battery thermal management system (BTMS). As a hot topic in current BTMS research, boiling cooling technology with high heat transfer efficiency is a reliable way to solve these thermal management problems. In this study, a novel thermal management system for prismatic batteries based on cooling by non-contact flow boiling is proposed, and various cold-plate structures are considered with different numbers and locations of coolant inlets and outlets inside the cold plate cavity, and with different numbers and arrangements of ribs and fins. A three-dimensional transient model was conducted to investigate the effect on the cooling performance of the boiling BTMS of several variables — notably inner-channel design schemes, the number of ribs or fins in the cold plate, coolant inlet temperatures, and inlet Reynolds numbers. The results indicate that among the six design schemes that were considered, the best comprehensive heat transfer performance is achieved with two pairs of inlets and outlets, a vertical fin arrangement, and fin height equal to 3/4 of the inner channel dimension. With an increase in the number of fins, the maximum temperature and maximum temperature difference of the structures that were considered decrease by no <0.8 °C and 0.2 °C, respectively. Also, the temperature uniformity of the battery pack can be improved by appropriately increasing the coolant inlet temperatures and reducing the inlet coolant flow rate. When the number of fins is 19, the inlet temperature is 29 °C, and the inlet Reynolds number is 893, the preferred BTMS is always able to maintain its maximum temperature below 35.67 °Cand the maximum temperature difference to below 4.47 °C, at 3C high discharge rate.

Strengthening of melting-solidification process in latent heat storage through sine wave shaped fins

Phase change materials (PCMs) offer an effective way to store thermal energy and balance the supply-demand mismatch in time and space. The melting-solidification process in PCMs is of main importance for the performance of the storage. To improve this process, numerical analyses are performed with PCM in a 2-D square-form cavity with two discrete heat sources and wavy sinusoidal shaped fins. The influence of different period and amplitude is analyzed to find the better fins arrangement. For the melting process, when the fin period is 20 and the amplitude is 2, the complete melting time of PCM is the shortest. In addition, fins with larger heat transfer area do not show better performance. For the solidification process, the optimal arrangement of fins is fins with period of 10 and amplitude of 5. The complete melting time can be shortened by more than 20.8 % and the complete solidification time could be shortened by more than 19 % compared to the case without any fins. Furthermore, in this study, the natural convection in the melting process is greatly affected by the fin area. When the fin area is large, the average value of natural convection is small, resulting in the maximum and minimum shortening of PCM melting time of 35.6 % and 20.8 %, respectively. The increase of fin area shows good heat transfer enhancement at the beginning of both melting and solidification process, but this strong strengthening effect does not continue throughout the melting/solidification process.

Design optimization of a novel annular fin on a latent heat storage device for building heating

The poor heat transfer performance of the heat exchanger leads to low heat storage efficiency of the latent heat storage device. To improve the heat transfer performance of the heat exchanger, a novel annular fin with inclined angle is proposed to enhance heat transfer of the heat exchanger. 12 fins with different structural parameters are designed and welded to the inner tube wall of the heat exchanger. The simulation model is in good agreement with the literature and the model is considered to be reliable. Based on the enthalpy-porosity model, the liquid fraction, temperature distribution, melting front, energy storage density and heat storage rate were used to compare and optimize the structural parameters of the annular fins. Results demonstrated that the difference in complete melting time due to the number of fins, fin arrangement, fin length and fin angle were 43 min, 85 min, 17 min and 10 min, respectively. The fin arrangement was the most significant in reducing the heat storage time. Compared to N = 4 and uniformly distributed fins, non-uniformly distributed fins reduced the total melting time of stearic acid by 53.13 % and 20.54 %. To be conclusive, the addition of non-uniformly distributed annular fins with 70° inclination enhanced the heat transfer in the heat exchanger and saved a significant amount of heat storage time.

A comparative numerical study about the impact of rectangular and T shaped fins on melting of PCM in a rectangular enclosure

A comparative numerical study is performed on the melting of RT42 phase change material (PCM) in a rectangular enclosure using two basic fin geometries: a regular fin and a flanged fin (T-shape) having a constant fin area. Five cases of each fin type, representing ten double fin arrangements, based on an upper (Lu) and lower fin (Ld) length ratio were examined. Hence, for cases I(I’), II(II’), III(III’), IV(IV’), and V(V’), theLu/Ld ratio is 1, 1.5, 4, 0.67, and 0.25, respectively. Furthermore, two more cases (VI and VII) with a single flanged fin at the upper and lower position were considered with flanged (Lf) to web (Lu, d) ratio of 0.136. Five performance indicators were employed: total melting time (tm), total stored energy (Et), average Nusselt number (Nu¯), mean power (Pm), and cost per mean power (Cpw) to evaluate the effect of fin geometry on the heat transfer mechanism governing the melting of PCM. An enthalpy-porosity model governed the phase change process. The mathematical models were simulated and verified against the reference theoretical results in ANSYS 2020 R2, CFD software. Mesh and time independent studies were also performed, and a time step of 0.1 s and 26,026 quad cell elements were recommended for a balanced computational accuracy and cost. The result shows that for the double fin arrangement cases, a decrease in the tm was observed as the Lu/Ld ratio was decreased. Case V, with the regular fin of Lu/Ld ratio 0.25, has the maximum melting rate and completely melts the PCM in 3696 s. However, the single flanged fin at the lower position (case VII) melts the PCM entirely in 2940 s, which is 41.2 % and 20.45 % faster than case I and V, respectively. Each case stores approximately the same amount of energy over time. However, for case VII, a high latent and sensible heat absorption rate was observed, followed by cases V and V’. Also, the Pm for case VII is 163 W, 71.32 %, and 25.66 % higher than case I and V, respectively. For the cost analysis, Cpw is employed, a ratio of the system’s total cost ($ 43.2) to the Pm. The Cpw for case VII is 0.27 $/W, 40 %, and 18.2 % less than case I (0.45 $/W) and V (0.33 $/W). The above result indicates that the double fin geometry can be replaced with a single flanged fin system for a high melting rate and low Cpw. Hence, a further study is required based on flanged to web ratio (Lf/Ld) and the positioning of the single flanged fin. A minimum tm (2806 s) and Cpw (0.252 $/W) were obtained for the Lf/Ld ratio of 0.25, placed 15 mm above the bottom of the container.

Comparison of different designs of solar air heater with the simple solar heater of having reflecting mirrors

In this research paper, three different arrangements of Solar Air Heaters (SAH) have been modeled and experimentally analyzed. The first solar heater is the Simple Solar Air Heater with tin cans, second has added reflecting mirrors with tin cans and third has a triangular fins arrangement on a copper plate. The outlet temperature of the air, solar heater efficiency, pressure drop, exergy, and exergy destruction have been determined for three arrangements of solar air heaters and compared with each other. The best performer SAH among the three was finally validated with the previous study on evacuated tube pipe solar air heater. After experimental and modeling results, it is concluded that the performance of evacuated tube pipe solar heater is better than tin cans reflecting mirror solar air heater in morning and evening and at noon the performance of reflecting mirror solar air heater is better since the addition of reflecting mirrors increase the heat supplied on the tin can tube in the afternoon time.

Multi-objective optimization of printed circuit heat exchanger with airfoil fins based on the improved PSO-BP neural network and the NSGA-II algorithm

The printed circuit heat exchanger (PCHE) with airfoil fins has the benefits of high compactness, high efficiency and superior heat transfer performance. A novel multi-objective optimization approach is presented to design the airfoil fin PCHE in this paper. Three optimization design variables (the vertical number, the horizontal number and the staggered number) are obtained by means of dimensionless airfoil fin arrangement parameters. And the optimization objective is to maximize the Nusselt number (Nu) and minimize the Fanning friction factor (f). Firstly, in order to investigate the impact of design variables on the thermal-hydraulic performance, a parametric study via the design of experiments is proposed. Subsequently, the relationships between three optimization design variables and two objective functions (Nu and f) are characterized by an improved particle swarm optimization-backpropagation artificial neural network. Finally, a multi-objective optimization is used to construct the Pareto optimal front, in which the non-dominated sorting genetic algorithm II is used. The comprehensive performance is found to be the best when the airfoil fins are completely staggered arrangement. And the best compromise solution based on the TOPSIS method is identified as the optimal solution, which can achieve the requirement of high heat transfer performance and low flow resistance.

Effect of open-ring pin fin arrangement on the thermal performance and entropy generation of a heat sink cooled by biologically synthesized silver-water nanofluid

Thermal performance of a heat sink having open-ring pin fins (ORPF) and cooled by biologically synthesized silver-water nanofluid is explored in terms of first and second laws of thermodynamics within the present work by focusing on the arrangement of ORPFs, namely the in-line and staggered ones. Influences of four different volumetric fractions of nanoparticles (φ=0–1%) and four different Reynolds numbers (Re=500–2000) on the thermal performance and entropy generation behavior of the nanofluid are numerically evaluated. Outcomes revealed that the convective heat transfer coefficient is improved by up to 71% and 19.3% in the in-line, and 65% and 24.7% in the staggered ORPF configurations, respectively, due to the increment in Re and addition of nanoparticles (at Re=500). Moreover, a decline in the pumping power is noticed by adding φ=1% of nanoparticles at Re=1500, compared to base fluid. The pumping power, on the other hand, is increased by 10.5% at Re=2000 and φ=0% when staggered configuration is considered instead of in-line one. Thermal and frictional entropy generation rates are remarkably reduced by incorporation of nanoparticles. In addition, using staggered ORPF arrangement instead of the in-line one can decrease the frictional and thermal entropy generation rates by up to 17% and 4.4%, respectively, at Re=2000.

A novel petal-type battery thermal management system with dual phase change materials

Phase change material (PCM) cooling is a prominent approach for battery thermal management. However, its application scenario is severely limited by the narrow range of phase change temperature. When the temperature of PCM does not reach the phase change temperature range, it is either a pure thermal conductive material or a completely molten liquid material, neither of which can play a role in battery thermal management. The present study proposes a novel petal-type battery thermal management system (BTMS) with dual PCMs, which has significantly enhanced the environmental adaptability of the battery based on PCM cooling. The thermal performance of the BTMS at different ambient temperatures and discharge rates is investigated by numerical simulation methods. The results show that when the battery is discharged at 1∼5C at an ambient temperature of 25°C, the maximum battery temperature (Tmax) is 29.87°C, 32.89°C, 34.69°C, 36.84°C, and 39.41°C, respectively. When the battery is discharged at 2C at 20°C, 30°C and 40°C, the Tmax is 30.49°C, 34.16°C and 43.70°C, respectively. Compared with the other two conventional BTMSs using a single type of PCM, the thermal performance and environmental adaptability of the proposed BTMS is the best under the three typical ambient temperatures. Furthermore, the above BTMS is optimized using fin-reinforced heat transfer technology in this paper. Compared to the BTMS without fins, the optimized solution 2 with asymmetric fin arrangement reduces the maximum temperature difference (ΔTmax) by 5.53% and 29.19% and the maximum temperature rise (ΔTmrise) by 36.15% and 42.76% at ambient temperatures of 30°C and 40°C.