Fin Heat Transfer Research Articles

Heat transfer and thermal analysis in a semi-spherical fin with temperature-variant thermal properties: an application of Probabilists’ Hermite collocation method

Finned surfaces are utilized in several industrial and technological applications including radiators in cars, air conditioning systems, and computer CPU heat sink to dissipate heat through convection or radiation. In this regard, the heat transfer enhancement utilizing the fins has received more attention in the scientific field. Motivated by this, the present research explicates temperature variation through a convective-radiative semi-spherical fin (SSF) with internal heating by taking into consideration of linear and nonlinear temperature-dependent heat transfer coefficient and thermal conductivities. Furthermore, the efficiency and heat transfer aspects of the fin are elaborated. The Rosseland approximation is used in this study to analyze radiation heat exchange. The developed energy equation is converted to a nonlinear ordinary differential equation (ODE) using dimensionless terms, and the probabilists’ Hermite collocation method (PHCM) is used to solve this problem. The governing parameters have been varied in their appropriate ranges to illustrate their impact on the thermal profile, and the results have been portrayed graphically. Some notable key findings of the current analysis are that as the scale of the convection–conduction and the radiation number upsurges, the thermal distribution through SSF drops. On the other hand, thermal distribution escalates for heat generation and thermal conductivity parameters.

Pre-research on Enhanced Heat Transfer Method for Special Vehicles at High Altitude Based on Machine Learning

The performance of an integrated thermal management system significantly influences the stability of special-purpose vehicles; thus, enhancing the heat transfer of the radiator is of great significance. Common research methods for radiators include fluid mechanics numerical simulations and experimental measurements, both of which are time-consuming and expensive. Applying the surrogate model to the analysis of the flow and heat transfer in louvered fins can effectively reduce the computational cost and obtain more data. A simplified louvered-fin heat transfer unit was established, and computational fluid dynamics (CFD) simulations were conducted to obtain the flow and heat transfer characteristics of the geometric structure. A three-factor and six-level orthogonal design was established with three structural parameters: angle θ, length a, and pitch Lp of the louvered fins. The results of the orthogonal design were subjected to a range analysis, and the effects of the three parameters θ, a, and Lp on the j, f, and JF factors were obtained. Accordingly, a proxy model of the heat transfer performance for louvered fins was established based on the artificial neural network algorithm, and the model was trained with the data obtained by the orthogonal design. Finally, the fin structure with the largest JF factor was realized. Compared with the original model, the optimized model improved the heat transfer factor j by 2.87%, decreased the friction factor f by 30.4%, and increased the comprehensive factor JF by 15.7%.

Enhancing solar stirling engine performance through the use of innovative heat transfer fin shapes

One of the challenges in designing and optimizing solar energy systems is achieving maximum power and efficiency at the lowest cost. This study focuses on using heat transfer fins to enhance energy absorption in the heater section of a solar Stirling engine. To begin, we model a parabolic solar collector system, considering factors that influence the amount of heat transfer to the heater section of the Stirling engine. Next, we model the Stirling engine using the PSVL model, which accounts for factors such as gas leakage, the temperature distribution in heat exchangers, longitudinal heat loss, polytropic heat transfer in cylinders, and other effects. In this paper, we also propose modifications to the basic model and introduce heat transfer fins made of FGM, with unique geometry and variable thickness, on the heater section of the solar Stirling engine to increase the heat received by the working fluid. We perform a thermal analysis of the fins to evaluate their impact on the heat the Stirling engine receives, including the effects of convection and radiation on the environment. We find that using these new fins in the heater section of the Stirling engine significantly increases the power and efficiency of the system.

Comparative Analysis of Heat Transfer of Engine Fins with different Materials in Steady State Condition

Comparative Analysis of Heat Transfer of Engine Fins with different Materials in Steady State Condition

Heat transfer and flow resistance performance of nonuniform distributed serrated fins

This article numerically investigates the behavior of nonuniform distributed serrated fins including equaled, shortened, lengthened, short on both sides, and long on both sides. In outputs, not only the temperature field and velocity contour but also the synergy field were examined. The results show significant advantages of nonuniform fins, having certain characteristics, in improving the overall heat transfer performance. At the near entrance of nonuniform fin type, heat transfer can be improved by increasing fin length gradually, while it becomes worsened by decreasing fin length. The length of the first fin in the near inlet region has a great influence on the distribution of the temperature field. For the best array compared with the uniform case, the Colburn j factor increased by 9.1 − 16.8%. Either uniform or nonuniform fin type deteriorates the flow resistance while heat transfer capability is enhanced. From the perspective of synergy between temperature gradient and velocity, the local field synergy angle at the near inlet region, and the windward side of the fin has a decisive effect on the heat transfer performance.

Design, fabrication, and testing of heat conduction apparatuses at a low cost

This article presents the design, fabrication, and testing of three heat conduction apparatuses needed for engineering students. These devices are the axial heat transfer apparatus (AHTA), radial heat transfer apparatus (RHTA), and fin heat transfer apparatus (FHTA). These three devices allow students to undertake experiments in conduction heat transfer. The laboratory staff, with the help of third- and fourth-year classes, took this effective step to carry out experiments related to the heat transfer course. The use of surplus materials and locally available low-cost new instruments make them suitable for performing successful laboratory experiments at an affordable cost. The total cost of the three devices is 750 US$. Currently, the devices are in service and show excellent performance. The devices and experiments demonstrated in this work are simple and easy to create. Their design and fabrication are based on tools that are readily available in an engineering department. The experiments achieve important aspects in the study of heat transfer, which enhances students’ understanding of the conduction mechanism in solids.

Dimensionless analysis of thermal contact resistance impact on heat transfer performance of rectangular fins applied in nuclear plant

This work aims to investigate the effects of welded Thermal Contact Resistance (TCR) on heat transfer for rectangular fins applied in passive nuclear plant. The dimensionless equations are established to describe fin efficiency and overall surface efficiency when subjected to TCR. An experimental set-up using a hot box are developed， and 18 experiments of fins with bilateral fillet welding (BFW) and unilateral penetration welding (UPW) are performed to obtain the range of TCR. Results show that the TCR values are about 0.006 and 0.002 (m2 K)/W for BFW and UPW, respectively. Dimensionless fin efficiency ηf' and overall surface efficiency η0' are governed by several dimensionless parameters that group thermal resistance, important material properties, and geometric parameters of the fin or substrate. TCR has a remarkable effect in the range of 10−4<Bi < 10−2, and the adverse effect of TCR on ηf' and η0' can be weakened by changing the geometric dimensions or material properties in a certain range.

Correlation development and parametric investigation for thermal–hydraulic characteristics of flying-wing fin

The present study investigates thermal–hydraulic characteristics and structural parameters of the flying-wing fins. 165 cases based on the response surface method (RSM), considering 6 geometric parameters, are carried out. Firstly, the correlations of the flying-wing fin's heat transfer (j-factor) and flow friction (f-factor) are proposed using numerical simulations. The maximum deviations of the correlation with j-factor and f-factor are 8.53 % and 9.51 %, respectively. Secondly, the effects of geometric parameters are investigated respectively using the RSM model in detail at Re of 3000. The j-factor and f-factor are positively correlated with fin pitch (Fp) and amplitude (A) while negatively correlated with wavelength (L) and fin height (Fh). The j-factor and f-factor rise and subsequently drop as the inclined angle (θ) increases. Evaluating the thermal performance shows that the optimum θ is 80°. The f-factor has a turning point at the angle of 75°. Regarding the effects between parameters, the lower f-factor can be obtained at large Fp when the fin is short while at small Fp when the fin is tall. The A and Fh change the trend of θ on j-factor and f-factor. Eventually, optimized geometrical parameters of the flying-wing fin are obtained by the desirability approach at Re = 3000.

Analysis of periodic heat transfer through extended surfaces

This article is concerned with the review of periodic heat transfer through extended surfaces known as fins. In this review, we bring out the detailed study of heat transfer of detailed type variation through extended surfaces. Heat transfer has remained a warm area responder to various conditions for the researchers in last many decades. In the current analysis, an attempt is appointed to study, analyze and summarize the result of the periodic heat transfer and flow in various fins. Further, we carried out the analysis for have carried heat transfers through various kinds of extended surfaces also called fins in the presence of periodic base and ambient temperature. The performance of the extended surface is expressed in terms of fin effectiveness and efficiency. The heat transfer process is regulated by three experimentally determined dimensionless parameters such as the frequency parameter, w, the convectional fins parameter, N, and the amplitude parameter, A. Further the fins performance and efficiency arfins? monstrated through several examples. On basis of comparison rectgular fins are good for heat transfer to its extended surfaces.

INVESTIGATION ON HEAT TRANSFER IN CIRCULAR FINS WITH H-SHAPED CAVITY USING FINITE ELEMENT METHOD AND CONSTRUCTAL DESIGN

Through constructal design, this study examines how the geometrical configuration of channels embedded within an object in the presence of internal heat generation can be utilized for cooling through convection heat transfer. During the present study, the cavity is cooled by the convection heat transfer method. This work aims to provide an optimal tree structure for cooling electronic components with circular dimensions and internal heat generation in an H-shaped cavity. A structure for this purpose must be designed so that the maximum temperature obtained in the desired surface area is reduced to the minimum for a given production heat power. A study will also examine the dimensions of specific channels in order to decrease the maximum temperature that will be produced. In addition, it will study the geometric characteristics of the branching of the channels and their length. The finite element method will be used to simulate the heat transfer process. Following the validation of the created model, numerous parameters will be checked on the maximum temperature generated in the system. The results will be presented and discussed in appropriate charts and tables.

Mathematical and Computer Modeling of the Forms of Multi-Zone Fuel Elements with Plates

Seeing the significant increase in the number of nuclear power plants, as well as models and modifications of nuclear reactors, it becomes important to find out/establish the advantages of certain plants. At the same time, designers face a number of questions for which optimal solutions have not yet been found. At nuclear plants, there is the largest turnover of financial funds and the smallest gain in economy brings huge profits, but one should not forget about reliability and costs during the plant construction. This is a complex problem that is solved at the design stage. Calculations of the reactor at the design stage make it possible to determine the main parameters of the active zone, temperature values, etc. Thermohydraulic calculation of the active zone of the reactor is one of the cornerstones in justifying the safe operation of the nuclear power plant. Calculations of coolant parameters and temperatures of fuel elements are carried out at all stages of designing and proving the safety of nuclear power plants. Twisted pipes and finned heat transfer surfaces are widely used in engineering to increase the effective heat transfer coefficient. In particular, longitudinal, transverse, and spiral edges are used for finning the shells of fuel elements of nuclear reactors and the outer surfaces of steam generator pipes. Finning not only increases the heat transfer surface on the side where the heat transfer coefficient has a low value, but also significantly affects the hydrodynamics of the flow, and thus affects this coefficient. It is obvious that the better the medium is mixed in the main flow and in the intercoral zone, the higher the heat transfer coefficient is. The most profitable forms of fuel elements shells finning are chevron and polyzonal finning, which are performed in the form of a multiturn spiral with a large step. The R-function theory turned out to be quite convenient for building mathematical models of finned shells of fuel elements with straight and helical plates, as well as for building the corresponding objects on a 3D printer. From a practical point of view, the relevance of the problem is also determined by the significant spread of twisted cylindrical bodies, twisted channels, coils in the energy, chemical, oil, gas, metallurgical industries and in heat engineering equipment. The flows that arise at this time make it possible to intensify the processes of heat and mass exchange and achieve savings in energy resources

Design Analysis of Heat Sink Using the Field Synergy Principle and Multitarget Response Surface Methodology

This study describes a novel heat sink design approach employs the field synergy concept and multitarget response surface methodology (RSM). The multiobjective response surface methodology can be used to determine the simulation equations that will maximize the heat transfer of fins at various fin heights, fin angles, and fin circumferences, when considering the impact of jet flow heat exchange. The goal of the response value was to maintain the minimum possible average field coangle and fin temperature. The results show that the ideal heat sink size would be the following: fins with a height of 50 mm, an angle of 60 degrees, and the number of fins equal to five. We examined the impact of wall speed on the heat transfer caused by the field synergy angle. Our findings suggest that with the synchromesh of the display field, heat-dissipation efficiency rises.

Heat transfer and pressure loss characteristics of an offset fin with oblique waves

An offset fin with oblique waves (OFOW) which is a combination of offset fin (OSF) and V-shaped oblique wavy fin (OWF) has been proposed to further enhance heat transfer in single phase laminar flows. The heat transfer and pressure loss characteristics of different configurations of the OFOW are investigated numerically. The 3D unsteady periodic model with the H1 thermal boundary condition is adopted to explore the effects of V wave pointing direction, phase angle and wave amplitude. The local distributions of velocity, secondary flow, wall shear stress and heat flux as well as friction factor f and Colburn factor j are presented and compared with those of the plain channel, OSF and OWF with the same aspect ratio and hydraulic diameter. It is found that the OFOW can further enhance heat transfer than the OSF and OWFs, i.e., at Re ≈ 400 with wave amplitude of A = 0.3, the Colburn factor j is around 4.2 times of that of the plain channel. It is shown that opposite V wave pointing directions in the successive offset plates cannot induce long-range counter-rotating vortices, and V wave amplitude A is the most dominant parameter, where wave pointing direction and phase angle in the successive offset plates have minor effects.

Numerical investigation of the air-side performance of louver fin-and-tube radiators having rectangular, tapered and airfoil section configuration

As the most widely used type in automobile industry, louver fin-and-tube radiator plays an important role in maintaining the stable operation of automobile. In order to further improve the heat transfer and flow performance on the basis of the original rectangular louver fin, a new type of airfoil louver fin was designed in this paper, and the air-side performance of airfoil, tapered and rectangular louver fin under different geometric parameters was numerically simulated by computational fluid dynamics (CFD). A total of fourteen samples are made and simulated with the corresponding louver angle (θ) being 23°, 26° and 29° and the louver length (Fl) are 1.2 mm, 1.4 mm and 1.6 mm respectively. The results reveal that the airfoil louver fin had the highest Nusselt number (Nu) and minimum friction factor (f) for all the studied cases. The Nu for the airfoil louver fin can be increased up to 4.9% over the rectangular louver fin and the corresponding pressure difference decreased up to 16.6%. However, because the heat transfer area of airfoil and tapered louver fin is slightly lower than that of rectangular louver fin, the heat transfer of airfoil and tapered louver fin is slightly lower than that of rectangular louver fin at θ=26° and 29° and low air inlet velocity. When the air inlet velocity is further increased, the heat transfer of airfoil and tapered louver fin is slightly higher than that of rectangular louver fin. Likewise, the heat transfer of airfoil and tapered louver fin is also slightly lower than that of rectangular louver fin for Fl=1.4mm and 1.6 mm. The heat transfer of airfoil louver fin is the highest at θ=23° and Fl=1.2mm.

Enhancement mechanism on heat and mass transfer of tall fin with cycloid thermosyphon loop

The aluminum fin integrated with thermosyphon loop is a good alternative for improving the thermal dissipation from the heat source, which has light-weight and high-efficiency features due to the charge of phase change working fluid. However, the criteria for flow channel arrangement and corresponding heat transfer mechanism in thermosyphon fins are still not clearly acknowledged. In present study, the cellular thermosyphon fin (CET fin) and the cycloid thermosyphon fin (CYT fin) are experimentally tested. Result shows that the CYT fin always illustrates much better temperature distribution and performs about 10.1% improvement on the average thermal resistance. Then, the pool boiling and condensation in CET and CYT fins are further explored via numerical investigation. It is found that the existence of vapor cavity in blind channels may enhance the condensation as well as promote the liquid level on the heat source side. Consequently, a total of four optimized configurations based on the tested CYT fin are proposed and numerically studied. Result shows that the optimum configuration with four vapor zones in one partition (4-in-1 case) possesses 8.7% higher liquid level compared with the original CYT fin. The increments on the evaporation rate and condensation rate can reach 12.7% and 10.7%, respectively, and lower fin root temperature is also achieved.

A novel passive solar vertical-finned-thermocatalytic-Trombe wall system for air purification and heating

In this study, the combination of thermocatalytic oxidation technology with finned heat transfer technology was proposed to produce a novel passive solar vertical-finned- thermocatalytic-Trombe wall (VFTC-Trombe wall) system. The numerical model coupled with flow and heat transfer, convective-diffusion and catalytic reaction kinetic processes was established. The influences of fins geometry and environmental parameters on thermal and air purification performance were evaluated. The main findings are as follow: Both the purification efficiency and total efficiency increase with fins height. As the fins spacing rises, thermal, purification and total efficiencies all show maximum values. By adding the vertical fins in the channel, the purification performance improvement of the TC-Trombe wall system can be realized without sacrificing thermal performance. The optimum purification efficiency improves more than 1.5 times compared to that without vertical fins. The vertical fins have more significant effect on the purification performance than the thermal performance. At fins height h = 40 mm, fins spacing s = 16.67 mm, and solar radiation intensity I = 400 W/m2, the maximum total efficiency of VFTC-Trombe wall system reaches 65.11%, which is relatively improved by 31.9% compared to the TC-Trombe wall system without vertical fins. In addition, the impact of ambient temperature on thermal performance is more significant than that on purification performance.

Studying transient heat transfer in a cylindrical pin fin with radiation and convection

A simple experimental fin device was used to develop a laboratory procedure for undergraduate engineering students, in order to enhance their understanding of the transfer of thermal energy. This experiment exposes the student to several important concepts, namely one-dimensional, time-dependent heat transfer in extended surfaces by conduction, convection and radiation. In a few simple steps, students have the opportunity to compare the measured to the predicted temperature profiles obtained at different times using an analytical complex solution and to calculate convective and radiative heat coefficients, such as the relative predominance of convection heat transfer with respect to radiation.

Airside Thermal Performance of Louvered Fin Flat-Tube Heat Exchangers with Different Redirection Louvers

The performance of heat exchangers is severely limited by airside thermal resistance. The effect of redirection louvers (RLs) on the airside thermal performance of a compact flat-tube louvered fin heat exchanger was investigated. A steady-state 3D numerical analysis was conducted for different fin configurations by varying the number of RLs (NRL = 1, 2, 3, and 5). Conjugate heat transfer analysis was performed at the low Re (50–450) for domestic and transport air-conditioning applications. Geometric parameters such as louver pitch, louver angle, fin pitch, and flow depth were set as 1.7 mm, 27°, 1.2 mm, and 20 mm, respectively. The effective heat transfer fin surface areas of different fin configurations were also kept identical for a comparative analysis. The influence of the RLs on the airside thermal–hydraulic performance was analysed by exploring the local and average Nusselt numbers, pressure drop, Colburn j factor, friction factor f, performance evaluation criteria (PEC), and flow efficiency of different fin configurations. The numerical results revealed that the asymmetric fin configuration with two RLs (NRL = 2) showed the best heat transfer performance for the entire Re range. It resulted in a 33% higher average Nusselt number, causing a 24% higher pressure drop compared to NRL=5. At low flow velocities (Re &lt; 75), NRL = 3 showed better PEC; however, at high flow velocities (Re &gt; 75), NRL = 1 outperformed other fin configurations. Finally, it was noted that increasing the number of RLs reduced the amplitude of the wavy-shaped flow formed between the neighbouring louvered fin, consequently deteriorating the flow efficiency.

Analytical fin efficiency model for open-cell porous metal fins based on Kelvin cell assumption

Open-cell porous metals are widely used to enhance convective heat transfer of thermal management devices. In this paper, the open-cell porous metal structure was represented by a polyhedron model known as the Kelvin cell, and an analytical model for the efficiency of the porous metal fin attached to an isothermal surface was derived. The forced convective heat transfer coupled with heat conduction through the ligaments of porous metal was analyzed to derive the fin efficiency model. The effects of pore diameter, ligament diameter, and porous metal fin height on the fin efficiency and heat transfer rate of porous metal fins were also investigated. The new analytical fin efficiency model based on the Kelvin cell was compared with the fin efficiency evaluated using computational fluid dynamics analysis results; good agreement was found. The proposed analytical fin efficiency model avoids the numerical calculations required for heat transfer analysis of porous metals used as extended surfaces in many engineering applications such as heat sinks and heat exchangers, and can produce simple but effective results.

Application of He's homotopy and perturbation method to solve heat transfer equations: A python approach

In this research article, an attempt has been made to solve the linear/nonlinear and steady/unsteady heat transfer equations using the Homotopy and Perturbation method (HPM). Moreover, the implementation of HPM has been done by using SymPy, a library in python, to solve problems symbolically. Total three problems were dealt viz. steady-state conduction with heat generation, lumped capacitance analysis with a variable specific heat of the material, and heat transfer in uniform rectangular fin with radiation from the surface. In all the cases, the HPM has given excellent results compared to the analytical and numerical. Finally, the execution of SymPy has been explained, and a detailed procedure to implement HPM through python has been presented for all three cases.