Numerical Study of Heat Transfer in Rectangular Fins for Different Cases of Thermo-Physical Properties

2021 ◽  
Vol 408 ◽  
pp. 83-98
Author(s):  
Imene Bennia ◽  
Tawfik Benabdallah ◽  
Samah Lounis
Keyword(s):  
Heat Transfer ◽  
Numerical Study ◽  
Three Dimensional ◽  
Governing Equations ◽  
Unconditionally Stable ◽  
Additional Heat ◽  
Dimensional Simulation ◽  
Volume Method ◽  
Thermo Physical Properties ◽  
Calculation Code

The present work is a contribution to the development of a calculation code that determines the temperature field on fins having rectangular geometry for any bi-dimensional or three-dimensional simulation conditions. Different cases of simulations are presented. An implicit finite volume method, unconditionally stable, is extended in this study for the discretization of the governing equations. The representative results, validated by the Ansys code, show that the fin temperature increases with the increase of the temperature values selected as the boundary conditions, with the addition of a heat flow or any additional heat source. The numerical results are very consistent with the theory and the results obtained from commercialized codes. By increasing the diffusivity one converge more quickly towards the stationary solution. Upon reducing the fin size a very drastic shift occurs from the transient regime to a permanent one. In the case of a refinement of the mesh, the use of a very small epsilon ensures the convergence. Therefore, the results obtained in this study serve as basis of comparison with any other study on heat transfer on rectangular fins.

scholarly journals Numerical Study of the Turbulent Natural Convection in a Trapezoidal Cavity: Influence of the Inclination of the Lateral Walls

2020 ◽  
Vol 14 ◽  
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Numerical Study ◽  
Boussinesq Approximation ◽  
Governing Equations ◽  
Square Cavity ◽  
Turbulent Natural Convection ◽  
Side Walls ◽  
Volume Method ◽  
Calculation Code

In this paper, we study the heat transfer in turbulent natural convection in a two- dimensional cavity with a trapezoidal section and isoscales filled out of air with as height H =2.5 m. In these conditions, the side walls are differentially heated while the horizontal walls are adiabatic. The k-ε turbulence model with a small Reynolds number was integrated in our calculation code. The governing equations of the problem were solved numerically by the commercial CFD code Fluent; which is based on the finite volume method and the Boussinesq approximation. The elaborated model is validated from the experimental results in the case of the turbulent flow in a square cavity. Then, the study was related primarily to the influence of the slope of the side walls of the cavity on the dynamic behavior and the heat transfer within the cavity.

Effect of Periodic Imposed Heat Flux on Three-Dimensional Natural Convection in a Partially Heated Cubical Enclosure

2016 ◽  
Vol 831 ◽  
pp. 83-91
Author(s):  
Lahoucine Belarche ◽  
Btissam Abourida
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Numerical Study ◽  
Control Volume ◽  
Vertical Wall ◽  
Three Dimensional ◽  
Maximum Temperature ◽  
Cubical Enclosure ◽  
Simplec Algorithm ◽  
Volume Method

The three-dimensional numerical study of natural convection in a cubical enclosure, discretely heated, was carried out in this study. Two heating square sections, similar to the integrated electronic components, are placed on the vertical wall of the enclosure. The imposed heating fluxes vary sinusoidally with time, in phase and in opposition of phase. The temperature of the opposite vertical wall is maintained at a cold uniform temperature and the other walls are adiabatic. The governing equations are solved using Control volume method by SIMPLEC algorithm. The sections dimension ε = D / H and the Rayleigh number Ra were fixed respectively at 0,35 and 106. The average heat transfer and the maximum temperature on the active portions will be examined for a given set of the governing parameters, namely the amplitude of the variable temperatures a and their period τp. The obtained results show significant changes in terms of heat transfer, by proper choice of the heating mode and the governing parameters.

A Numerical Study of Three-Dimensional Convective Heat Transfer From a Window Covered by a Simple Partially-Open Plane Blind

2008 ◽  
Author(s):  
Patrick H. Oosthuizen ◽  
Murat Basarir ◽  
David Naylor
Keyword(s):  
Heat Transfer ◽  
Numerical Study ◽  
Three Dimensional ◽  
Side Surface ◽  
Governing Equations ◽  
Three Dimensional Flow ◽  
Buoyancy Forces ◽  
Fluid Properties ◽  
Higher Temperature ◽  
Open Plane

Heat transfer from the room-side surface of a window covered by a plane blind to the surrounding room has been considered. The window is at a higher temperature than the air in the room. There is an open gap between the blind system and the window at the top of the window and the effect of the size of this gap on the window-to-air heat transfer rate has been numerically examined. Three-dimensional flow has been considered. The flow has been assumed to be steady and laminar and it has been assumed that the fluid properties are constant except for the density change with temperature which gives rise to the buoyancy forces, this having been treated by using the Boussinesq approach. It has also been assumed that the flow is symmetrical about the vertical centre-plane of the window. The solution has been obtained by numerically solving the full three-dimensional form of the governing equations, these equations being written in terms of dimensionless variables. Results have only been obtained for a Prandtl number of 0.7. The effects of the other dimensionless parameters on the window Nusselt number have been numerically determined.

scholarly journals Numerical Study of Periodic Magnetic Field Effect on 3D Natural Convection of MWCNT-Water/Nanofluid with Consideration of Aggregation

Processes ◽  
2019 ◽  
Vol 7 (12) ◽  
pp. 957 ◽  
Author(s):  
Lioua Kolsi ◽  
Hakan Oztop ◽  
Kaouther Ghachem ◽  
Mohammed Almeshaal ◽  
Hussein Mohammed ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Numerical Study ◽  
Three Dimensional ◽  
Magnetic Field Effect ◽  
Oscillation Period ◽  
Governing Equations ◽  
Periodic Magnetic Field ◽  
Aggregation Effect ◽  
Volume Method ◽  
The Magnetic Field

In this paper, a numerical study is performed to investigate the effect of a periodic magnetic field on three-dimensional free convection of MWCNT (Mutli-Walled Carbone Nanotubes)-water/nanofluid. Time-dependent governing equations are solved using the finite volume method under unsteady magnetic field oriented in the x-direction for various Hartmann numbers, oscillation periods, and nanoparticle volume fractions. The aggregation effect is considered in the evaluation of the MWCNT-water/nanofluid thermophysical properties. It is found that oscillation period, the magnitude of the magnetic field, and adding nanoparticles have an important effect on heat transfer, temperature field, and flow structure.

scholarly journals Three-dimensional numerical simulation of a turbulent flow around an obstacle

2020 ◽  
Vol 307 ◽  
pp. 01006
Author(s):  
Benahmed Lamia ◽  
Aliane Khaled ◽  
Z. Sari Hassoun
Keyword(s):  
Numerical Simulation ◽  
Velocity Field ◽  
Kinetic Energy ◽  
Three Dimensional ◽  
Governing Equations ◽  
Ansys Cfx ◽  
Recirculation Zones ◽  
Rectangular Obstacle ◽  
Volume Method ◽  
Calculation Code

In this work we study the influence of the inclined shape of the lover and downstream edge of a rectangular obstacle. We analyze the dimensions of the recirculation zones, the velocity field, the kinetic energy and the pressure. A three-dimensional study was conducted using the ansys cfx calculation code. The turbulence model k-ԑ is used to model turbulence, and the governing equations are resolved by the finite volume method.

scholarly journals Numerical study on aerothermal performance of shroud movement in the vivinity of turbine tips

2020 ◽  
pp. 321-321
Author(s):  
Yunsong Zhang ◽  
Yongbao Liu ◽  
Yujie Li ◽  
Qijie Li
Keyword(s):  
Heat Transfer ◽  
Secondary Flow ◽  
Flow Structure ◽  
Numerical Study ◽  
Three Dimensional ◽  
Breakdown Point ◽  
Axial Direction ◽  
Suction Surface ◽  
Initial Location ◽  
Dimensional Simulation

In this paper, the effects of shroud movement on transonic flow and heat transfer in the vicinity of turbine tip was studied by using three-dimensional simulation of GE-E3 first-stage HPT. Aerothermal performance and flow structure were analyzed with and without turbine shroud moving, respectively. Based on the distribution of limiting streamlines and the vortex structures, the influential characteristics between the leakage flow and the secondary flow generated by shroud movement were studied. Moreover, the coefficient of heat transfer at the wall were investigated. Results show that the flow structure is changing with the movement of turbine shroud, and the location of the separation line changes significantly by the influence of the secondary flow. The leakage vortex initial location delayed in axial direction and its breakdown point located at 65% cross section. This accelerates the mixing loss and increase the perturbation. In addition, it is observed that the coefficient of average heat transfer is increased obviously by 54.8% in the region of shroud surface. However, this coefficient in the region of suction surface decreased by 11.9%.

scholarly journals Simulation and Analysis of a Turbulent Flow Around a Three-Dimensional Obstacle

2019 ◽  
Vol 13 (3) ◽  
pp. 173-180
Author(s):  
Lamia Benahmed ◽  
Khaled Aliane
Keyword(s):  
Shear Stress ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Turbulence Models ◽  
Governing Equations ◽  
Complex Behaviour ◽  
Ansys Cfx ◽  
Recirculation Zones ◽  
Volume Method ◽  
Calculation Code

Abstract The study of flow around obstacles is devised into three different positions: above the obstacle, upstream of the obstacle, and downstream of the latter. The behaviour of the fluid downstream of the obstacle is less known, and the physical and numerical modelling is being given the existence of recirculation zones with their complex behaviour. The purpose of the work presented below is to study the influence of the inclined form of the two upper peaks of a rectangular cube. A three-dimensional study was carried out using the ANSYS CFX calculation code. Turbulence models have been used to study the flow characteristics around the inclined obstacle. The time-averaged results of contours of velocity vectors <V>, cross-stream <v> and stream wise velocity <u> and streamlines were obtained by using K-ω shear -stress transport (SST), RANG K-ε and K-ε to model the turbulence, and the governing equations were solved using the finite volume method. The turbulence model K-ω SST has presented the best prediction of the flow characteristics for the obstacle among the investigated turbulence models in this work.

Experimental and Numerical Investigation of the Gas Side Heat Transfer and Pressure Drop of Finned Tubes—Part II: Numerical Analysis

2012 ◽  
Vol 4 (4) ◽  
Author(s):  
Rene Hofmann ◽  
Heimo Walter
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Numerical Study ◽  
Three Dimensional ◽  
Finned Tube ◽  
Renormalization Group Theory ◽  
Tube Material ◽  
Finned Tubes ◽  
Steady State Temperature ◽  
Volume Method

The heat transfer and pressure drop behavior of segmented circular and helical as well as solid finned tubes are investigated in a three-dimensional numerical study. The simulation is carried out using a finite volume method for calculating the steady-state temperature and flow field of the fluid as well as the temperature distribution of the tube material. For modeling the turbulence, the k-ε turbulence model based on the renormalization group theory (RNG) is used to resolve the near-wall treatment between adjacent fins. All simulations are performed in the Re range between 3500 ≤ Re ≤ 50,000. The influence of Reynolds number and fin geometry (segmented or solid and circular or helical) on the local and global averaged heat transfer and pressure drop was studied. A comparison between solid and segmented finned tube has shown that the heat transfer and pressure drop for the segmented finned tubes is higher. The numerical results are compared with experimental data.

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