Fin Heat Transfer Research Articles

A new approach in the design of heat transfer fin for melting and solidification of PCM

In this study, the effect of surface areas of heat transfer fins on the melting and solidification process of phase change material in thermal energy storage was investigated. The melting and solidification process of the PCM in the test domain was investigated by experimental and numerical analysis. Non-melting regions in TES were identified and special heat transfer fins were designed to melt these regions. The designed fins were compared with the heat transfer fins which are highly preferred in the literature. The results showed that the surface area of fins has positive effects on heat transfer, but negative effects on natural convection current. The surface area of Fin 1_C extending throughout the TES is 5 times the surface area of Fin 2 designed in the scope of the study. PCM melted with Fin 2 in 64 min, but it melted with Fin 1_C in 60 min. The best melting process in the melting of PCM (Paraffin wax - RT 55) in the TES was provided with Fin 4 design. The melting time has been improved by 65% with the specially designed Fin 4. In all thermal energy storage designed and considered during the solidification process, no significant difference could be obtained. The main reason for this is thought to be the effect of overcooling.

Numerical Simulation of Flow and Heat Transfer in LPD Type Misaligned Fins

With the rapid development of all walks of life, heat exchangers have been used all over the various fields. Plate fin heat exchanger was concerned, because of its high heat transfer rate and the small size. Among them, the offset strip fin is called “high efficiency fin” because its special staggered arrangement structure can increase the turbulent flow of fluid and enhance heat transfer. In order to study the influence of flow and heat transfer in dislocation fins, the three-dimensional numerical simulation of LPD dislocation fins is carried out by numerical simulation. Firstly, the accuracy of the standard laminar flow model is verified by using the dislocation fins and experimental data provided by the literature. The average error between the calculated value of the heat transfer factor and the experimental value is 5.95%, and the average error between the calculated value and the experimental value of the friction factor is 2.02%. On this basis, the influence of flow parameters and structural parameters on the internal flow and heat transfer in the dislocation fins is analyzed.The results show that: (1) the smaller the fluid velocity, the lower the height of the dislocation fin; the smaller the tooth angle, the shorter the cut length; the greater the heat transfer factor j, the better the heat transfer performance;(2) The higher the fluid velocity, the higher the height of the dislocation fin, the smaller the tooth angle; the shorter the cut length, the smaller the friction factor f, the better the resistance characteristic;(3) the lower the fin height, the smaller the tooth angle; the shorter the cut length, the greater the temperature difference and the pressure drop with the length of the heat transfer section; the fin height has little effect on the velocity field, The flow distribution of the fluid flow in the flow channel is affected, the shorter the cutting length is, the faster the velocity field changes.

CFD Analysis of Heat Transfer in Annular Fins of various Profiles having different Shapes of Perforation

CFD Analysis of Heat Transfer in Annular Fins of various Profiles having different Shapes of Perforation

Characteristics of Flow Symmetry and Heat Transfer of Winglet Pair in Common Flow Down Configuration

The effect of transverse pitch between a pair of delta-winglet vortex generators arranged in a common flow down configuration on the symmetrical flow structure and heat-transfer performance was numerically investigated. The results showed that symmetrical longitudinal vortices form a common flow down region between the vortices. The fluid is induced to flow from the top towards the bottom of the channel in the common flow region, which is advantageous to the heat transfer of the bottom fin. The vortex interaction increases and the vortex intensity decreases along with the decrease in transverse pitch of vortex generators. Vortex interaction has a slight influence on pressure penalty. The Nusselt number decreases with increasing vortex interaction. The vortices gradually attenuate and depart from each other during the process of flowing downward. A reasonable transverse pitch of delta-winglet vortex generators in a common-flow-down configuration is recommended for high thermal performance.

Investigation of Ti6Al4V and AA7075 alloy embedded nanofluid flow over longitudinal porous fin in the presence of internal heat generation and convective condition

The thermal attributes of porous fin due to radiation and natural convection have been carried out in the presence of nanofluid flow. The geometry of the fin taken for the analysis is rectangular profiled longitudinal fin. The temperature-dependent internal heat generation condition is also considered along with Darcy’s model. The two types of nanofluid containing titanium alloy () and aluminium alloy (AA7075) immersed in water is considered for the investigation. The modelled nonlinear ordinary differential equation is numerically solved by the Runge–Kutta–Fehlberg technique. The impact of geometric parameter on the heat transfer analysis of the fin due to the flow of both nanofluids is plotted and consequences are physically interpreted. It is observed that the presence of the water-based titanium alloy better enhances the fin heat transfer rate.

Examining effects of special heat transfer fins designed for the melting process of PCM and Nano-PCM

In this study, a new heat transfer fins design, which may improve melting in thermal energy storage, is proposed. First, the melting process in the thermal energy storage without fins is discussed. Then, heat transfer fins are designed to allow the melting of the non-melting regions in TES. These fins are compared with the most widely used fin types in the literature. Melting processes of Base and Nano PCMs with different heat transfer fins are also investigated. The results showed that the development of heat transfer fins has a positive contribution to enhance melting in thermal energy storage systems such as reducing the weight of TES and reducing costs of TES. It is observed that adding fin 2 reduces notably the melting time, but in terms of geometry, fin 1 is more effective in the melting process. In addition, it is found that when inserting fin 1, the PCM melts faster. The melting time has decreased by 63% with the placement of the designed fin in the heat storage tank. However, in the case without fin1, the Nano-PCM is partially melted. The melting ratio at t = 120 min is 98% and 36% for PCM and Nano-PCM, respectively.

Numerical Analysis of Transient Heat Transfer in Radial Porous Moving Fin with Temperature Dependent Thermal Properties

In this article, a time dependent partial differential equation is used to model the nonlinear boundary value problem describing heat transfer through a radial porous moving fin with rectangular profile. The study is performed by applying a numerical solver in MATLAB (pdepe), which is a centered finite difference scheme. The thermal conductivity and fin surface emissivity are linearly dependent on temperature while the heat transfer coefficient is given by power law function of temperature. The effects of thermo-physical parameters, such as the Peclet number, surface emissivity coefficient, power index of heat transfer coefficient, convective-conductive parameter, radiative-conductive parameter and non-dimensional ambient temperature on temperature are studied.

Heat transfer and flow characteristics of offset fin and flat tube heat exchangers under low pressure environment

Due to the performance degradation of the vehicle cooling system heat exchanger in the low pressure environment, the problem of overheating of the cooling system occurs when the vehicle is running on the plateau. This seriously affects the use of vehicles on the plateau environment. Therefore, it is necessary to study the influence of the plateau low pressure environment on the heat transfer and flow characteristics of the vehicle cooling system heat exchanger. In this paper, an experimental study of an offset fin and flat tube heat exchanger was conducted on a low pressure wind tunnel test bench, and the heat transfer and flow characteristics of the heat exchanger under different gauge pressure conditions were analyzed. Based on this, numerical simulations were carried out to study the heat transfer and flow characteristics of the heat exchanger with different structural parameters under low pressure environment. The empirical correlation of Colburn factor, j, and friction factor, f, were fitted using multiple linear regression. The research results can provide help for the engineering calculation of the offset fin and flat tube heat exchanger.

A new analytical solution of longitudinal fin with variable heat generation and thermal conductivity using DRA

In this paper, nonlinear differential equation for a longitudinal fin (LF) heat transfer with thermal conductivity and heat generation that depends on temperature is solved numerically by employing Runge–Kutta technique of fourth-order (RK4) featuring shooting technique and analytically via a new modified analytical technique called Duan–Rach method. The physical model of the heat transfer was utilized to examine the influences of the thermogeometric parameters, heat transfer rate and variable thermal conductivity on the temperature profile and efficiency of LF. The obtained outcomes show that the temperature profile of fin, heat transfer and the efficiency of the fin are considerably impacted by the fin factor of thermogeometric. The analytical outcomes by a new efficient algorithm are compared with the numerical computations of the RK4 featuring shooting techniques and various available literature outcomes to achieve the precision of the proposed technique. Obtained results show obviously the fidelity of the suggested approach. Flow model of longitudinal fin and the effect of thermogeometric parameter on dimensionless temperature distribution.

Numerical study of nanofluids effect on heat transfer and pressure drop of triangular microchannel heat sink

The present work deals with study the heat transfer and pressure drop of the triangular microchannel heat sink(MCHS), along different working fluids. The nanofluids such as CuO and Al2O3are used as coolants to enhance the performance of triangular microchannel heat sinks.The modeling and analysis were done with the help of Solid works. The heat transfer performance of the triangular fins were studied with the Reynolds number varying from 96 - 460. Thenumerical result shows that the triangular oblique finned microchannel heat sink has large heat transfer rateof 12.9 % for varying Reynolds number when compared to a straight channel. Similarly, the pressure drop also increases with 38.2% for triangular microchannel flowing nanofluid. Consequently triangular microchannel is enhancing the heat removed in electronics chip cooling

Determining Effects Of Heat Transfer Fins On The Solidification Process Of Pcm And Nano-Pcm With A Rectangular Cooler

In this study, the performances of the heat transfer fins during the solidification processes of PCM and nano-PCMS(Al 2 O 3 - CuO) were investigated. These two situations were considered for both with and without fins. Two different heat transfer fins were considered in the study. The investigation was carried out using both experimental (for Base-PCM) and numerical methods. The results showed that the effects of heat transfer fins were limited due to the overcooling effect of PCMs. The solidification process of Base-PCM in the heat storage tank ended in 10 minutes, while the solidification time of the PCM was determined as 11 minutes by using the Fin 1 design. The solidification process in the heat storage tank with nano-PCM (CuO) was realized in 13 minutes with the Fin 1 design.

A Numerical Research of Heat Transfer in Rectangular Fins with Different Perforations

Heat Transfer enhancement needs buoyancy force. This is to be achieved by making perforations on fin surfaces. The present paper is a study on the enhancement of heat transfer in terms of density, velocity and temperature with three different perforation geometry (parallel square, inclined square and circular). CFD was used to carry out the study of density variation, velocity and temperature drop among different perforated fins. This type of perforated fin has an improvement in heat transfer rate over its dimensionally equivalent solid fin.

Computational simulation and experimental validation of an engineering problem: A case study on heat transfer in cylindrical fin with phase‐change material

AbstractIn this study, an extensive numerical simulation on the fins with a phase‐change material (PCM) has been conducted under various design aspects to understand the heat transfer mechanism through a project‐based learning system. A detailed methodology on the use of computational fluid dynamics (CFD) tools for an engineering problem is discussed along with experimental validation. Initially, a required experimental test setup has been developed, and a cylindrical fin with PCM is fabricated and tested for heat transfer. Cylindrical fin is made from aluminum material, and paraffin is used as PCM since its application is widely spread in energy industries. Later, CFD simulation is performed on the cylindrical fin in ANSYS Workbench by including both heat transfer and phase‐change phenomenon of PCM. The CFD solver solves the partial differential equation through the finite volume method and the results obtained from the CFD simulation are checked for grid independence. Also, the obtained results are compared with experimental results for validation and found a good agreement. After validation, the influence of the PCM zone aspect ratio, PCM zone location, and groove over fin on heat transfer are numerically studied. From the obtained results, it is noticed that increasing the PCM volume increases the melting time and also lowers the fin tip temperature. Finally, fins with peripheral grooves and PCM proves as a good combination for a better heat transfer rate. This kind of simulation studies helps the students to understand the complex heat transfer mechanism through project‐based learning and also expertise the students.

3D coupled conduction-convection problem using in-house heat transfer experiments in conjunction with hybrid inverse approach

Purpose Many a times, the information about the boundary heat flux is obtained only through inverse approach by locating the thermocouple or temperature sensor in accessible boundary. Most of the work reported in literature for the estimation of unknown parameters is based on heat conduction model. Inverse approach using conjugate heat transfer is found inadequate in literature. Therefore, the purpose of the paper is to develop a 3D conjugate heat transfer model without model reduction for the estimation of heat flux and heat transfer coefficient from the measured temperatures. Design/methodology/approach A 3 D conjugate fin heat transfer model is solved using commercial software for the known boundary conditions. Navier–Stokes equation is solved to obtain the necessary temperature distribution of the fin. Later, the complete model is replaced with neural network to expedite the computations of the forward problem. For the inverse approach, genetic algorithm (GA) and particle swarm optimization (PSO) are applied to estimate the unknown parameters. Eventually, a hybrid algorithm is proposed by combining PSO with Broyden–Fletcher–Goldfarb–Shanno (BFGS) method that outperforms GA and PSO. Findings The authors demonstrate that the evolutionary algorithms can be used to obtain accurate results from simulated measurements. Efficacy of the hybrid algorithm is established using real time measurements. The hybrid algorithm (PSO-BFGS) is more efficient in the estimation of unknown parameters for experimentally measured temperature data compared to GA and PSO algorithms. Originality/value Surrogate model using ANN based on computational fluid dynamics simulations and in-house steady state fin experiments to estimate the heat flux and heat transfer coefficient separately using GA, PSO and PSO-BFGS.

Numerical Simulation of Dual-Phase-Lag Model and Inverse Fractional Single-Phase-Lag Problem for the Non-Fourier Heat Conduction in a Straight Fin

In recent years, many studies have been done on heat transfer in the fin under unsteady boundary conditions using Fourier and non-Fourier models. In this paper, unsteady non-Fourier heat transfer in a straight fin having an internal heat source under periodic temperature at the base was investigated by solving numerically Dual-Phase-Lag and Fractional Single-Phase-Lag models. In this way, the governing equations of these models were presented for heat conduction analysis in the fin, and their results of the temperature distribution were validated using the theoretical results of Single and Dual-Phase-Lag models. After that, for the first time the order of fractional derivation and heat flux relaxation time of the fractional model were obtained for the straight fin problem under periodic temperature at the base using Levenberg-Marquardt parameter estimation method. To solve the inverse fractional heat conduction problem, the numerical results of Dual-Phase-Lag model were used as the inputs. The results obtained from Fractional Single-Phase-Lag model could predict the fin temperature distribution at unsteady boundary condition at the base as well as the Dual-Phase-Lag model could.

Analysis of Conductive, Convective and Radiative Heat Transfer in Longitudinal Fins of Variable Profiles

The heat transfer enhancement by conduction, convection and radiation is still a topic of considerable attention in a number of areas and applications such as fin design despite the fact that numerous studies already exist in literature. In this study, the non-linear steady state heat equation is numerically solved for various fin surface profiles using the combined convection and the radiation modeling approach. The numerical solution is obtained using the Matlab® bvp4c package that is based on the shooting method. The results of this study indicate that the energy transfer by radiation is generally small compared to the transfers by conduction and convection but in situations where the fin base temperature is high, the radiation contribution can be significant and should be included when modeling the extended surface problems. However, it is acceptable to exclude the radiation energy transfer in some applications particularly when the fin thickness is small. The concept of Diminished Radiation Length (DRL) is introduced in this paper, which determines the length of the fin from the base at which the heat dissipation by radiation drops down to 0.4 Watts or less. The results presented in this paper can help the fin designers to select the appropriate fin parameters and decide whether the radiative heat loss is small enough to be neglected from the analysis.

Computational study of mixed convective heat transfer from a shrouded vertical dual-height plate fin array

Shrouded fin heat transfer has been investigated by many researchers in the recent time because of its broad applicability in engineering/industrial applications. Literature unveils the fact that almost all studies involving shrouded fin consider the fixed-height fin array. There is a limited literature in which it is predicted that dual-height fin array augments the heat transfer. These results are important since they require lesser material for enhanced heat transfer. In this present study, a computational code is developed to study the mixed convective heat transfer from a shrouded vertical dual-height plate fin array for possible improved heat transfer. Results indicate that induced velocity increases with decreasing reduced-height of fin for smaller fin spacing which enhances the heat transfer rate. Variation of friction factor multiplied by the Reynolds number (fRe) with the geometric parameters shows lower value for the case of dual-height fin array. Overall heat transfer coefficient shows improved results for the dual-height fin array involving lower Grashof numbers at different inlet velocities. But, for higher velocities, better results are noticed only in the case of larger clearances. The thermo-hydrodynamic performance parameter is found to be greater for the dual-height fin array than that of the fixed-height fin array. Computed axial pressure difference and overall Nusselt number are correlated with the governing parameters of the problem.

후퇴익형 형상의 와류발생기가 있는 핀휜 유동의 전열 및 유동 특성 분석에 관한 수치적 연구

후퇴익형 형상의 와류발생기가 있는 핀휜 유동의 전열 및 유동 특성 분석에 관한 수치적 연구

Temperature distribution analysis in a fully wet moving radial porous fin by finite element method

PurposeThis paper aims to study the temperature performance with natural convection and radiation effect on a porous fin in fully wet condition.Design/methodology/approachThe finite element method (FEM) is applied to generate numerical solution of the obtained non-dimensional ordinary differential equation containing highly nonlinear terms. The parameters which impact on the heat transfer of fin have been scrutinized by means of plotted graphs.FindingsThe porous fin is taken for the analysis in radial profile moving with constant velocity. Here, the thermal conductivity is considered to be temperature dependent. The Darcy’s model has been implemented to study the heat transfer analysis.Originality/valueThe paper is genuine in its type, and there are hardly any works on fins as per the authors’ knowledge.

Single- and multi-objective optimization of a plate-fin heat exchanger with offset strip fins adopting the genetic algorithm

Based on the new correlation for heat transfer and flow friction characteristics of the offset strip fins in our previous work, the single- and multi-objective optimizations of plate-fin heat exchanger by genetic algorithm are studied in this paper. Different objective functions of effectiveness, modified entropy number, and total annual cost are selected based on the first law of thermodynamics, the second law of thermodynamics and economic analysis. Comparative analysis of single- and multi-objective functions is conducted.The target with the maximum of the effectiveness is equivalent to the minimum of the entropy number generated by heat transfer. The poor thermodynamic performance of the total annual cost is mainly determined by the large proportion of operating costs in the total cost, the optimization process of which is focus on the minimum of the entropy number generated by pressure drop. The modified entropy generation number coordinates the comprehensive performance of the heat exchanger in both economic and thermodynamic aspects. The effective compromise of the single targets is achieved by the non-dominated sorting genetic algorithm with elite strategy (NSGA-II). The multi-objective optimizations are flexible in providing multiple solutions to the selection of practical production.