Thermal Analysis of an Internally Finned Tube Using a Porous Medium Approach

2002 ◽  
Author(s):  
Kyu In Shim ◽  
Jae-wook Yoo ◽  
Sung Jin Kim
Keyword(s):  
Thermal Analysis ◽  
Porous Medium ◽  
Finned Tube ◽  
Internally Finned Tube

Thermal Optimization of an Internally Finned Tube Using Analytical Solutions Based on a Porous Medium Approach

2007 ◽  
Vol 129 (10) ◽  
pp. 1408-1416 ◽  
Author(s):  
Kyu Hyung Do ◽  
Jung Yim Min ◽  
Sung Jin Kim
Keyword(s):  
Porous Medium ◽  
Analytical Solutions ◽  
Saturated Porous Medium ◽  
Equation Model ◽  
Finned Tube ◽  
Navier Stokes ◽  
Uniform Heat Flux ◽  
Thermal Optimization ◽  
Internally Finned Tube ◽  
Cylindrical Region

The present work deals with thermal optimization of an internally finned tube having axial straight fins with axially uniform heat flux and peripherally uniform temperature at the wall. The physical domain was divided into two regions: One is the central cylindrical region of the fluid extending to the tips of the fins and the other constituted the remainder of the tube area. The latter region including the fins was modeled as a fluid-saturated porous medium. The Brinkman-extended Darcy equation for fluid flow and two-equation model for heat transfer were used in the porous region, while the classical Navier–Stokes and energy equations were used in the central cylindrical region. The analytical solutions for the velocity and temperature profiles were in close agreement with the corresponding numerical solution as well as with existing theoretical and experimental data. Finally, optimum conditions, where the thermal performance of the internally finned tube is maximized, were determined using the developed analytical solutions.

Thermal analysis of a three-layered radiant porous heat exchanger including fluid flow simulation

2013 ◽  
Vol 228 (8) ◽  
pp. 1375-1390 ◽  
Author(s):  
M Sajedi ◽  
SA Gandjalikhan Nassab ◽  
E Jahanshahi Javaran
Keyword(s):  
Thermal Analysis ◽  
Porous Medium ◽  
Heat Exchanger ◽  
Thermal Radiation ◽  
Optical Thickness ◽  
Gas Flow ◽  
Flow Simulation ◽  
Local Thermal Equilibrium ◽  
Outlet Section ◽  
Energy Equations

Based on an effective energy conversion method between flowing gas enthalpy and thermal radiation, a three-layered type of porous heat exchanger (PHE) has been proposed. The PHE has one high temperature (HT) and two heat recovery (HR1 and HR2) sections. In HT section, the enthalpy of gas flow converts to thermal radiation and the opposite process happens in HR1 and HR2. In each section, a 2-D rectangular porous medium which is assumed to be absorbing, emitting and scattering is presented. For theoretical analysis of the PHE, the gas and solid phases are considered in non-local thermal equilibrium and separate energy equations are used for these two phases. Besides, in the gas flow simulation, the Fluent code is used to obtain the velocity distribution in the PHE from inlet to outlet section. For thermal analysis of the PHE, the coupled energy equations for gas and porous layer at each section are numerically solved using the finite difference method. In the computation of radiative heat flux distribution, the radiative transfer equation (RTE) is solved by the discrete ordinates method (DOM). The effects of scattering albedo, optical thickness, particle size of porous medium and inlet gas temperature on the efficiency of PHE are explored. Numerical results show that this type of PHE has high efficiency especially when the porous layers have high optical thickness. The present results are compared with those reported theoretically by other investigators and reasonable agreement is found.

Thermo-hydraulic performances of internally finned tube with a new type wave fin arrays

2016 ◽  
Vol 98 ◽  
pp. 1174-1188 ◽  
Author(s):  
Hao Peng ◽  
Lin Liu ◽  
Xiang Ling ◽  
Yang Li
Keyword(s):  
Finned Tube ◽  
Type Wave ◽  
Internally Finned Tube ◽  
New Type

Effect of fin and tube configuration on heat transfer of an internally finned tube

2015 ◽  
Vol 25 (8) ◽  
pp. 1978-1999 ◽  
Author(s):  
Kailash Mohapatra ◽  
Dipti Prasad Mishra
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Transfer Rate ◽  
Flow Characteristics ◽  
Finned Tube ◽  
Maximum Heat ◽  
Content Type ◽  
Maximum Heat Transfer ◽  
Internally Finned Tube ◽  
Fluid Flow Characteristics

Purpose – The purpose of this paper is to determine the heat transfer and fluid flow characteristics of an internally finned tube for different flow conditions. Design/methodology/approach – Numerical investigation have been performed by solving the conservation equations of mass, momentum, energy with two equation-based k-eps model to determine the wall temperature, outlet temperature and Nusselt number of an internally finned tube. Findings – It has been found from the numerically investigation that there exists an optimum fin height and fin number for maximum heat transfer. It was also found that the heat transfer in T-shaped fin was highest compared to other shape. The saw type fins had a higher heat transfer rate compared to the plane rectangular fins having same surface area and the heat transfer rate was increasing with teeth number. Keeping the surface area constant, the shape of the duct was changed from cylindrical to other shape and it was found that the heat transfer was highest for frustum shape compared to other shape. Practical implications – The present computations could be used to predict the heat transfer and fluid flow characteristics of an internal finned tube specifically used in chemical and power plants. Originality/value – The original contribution of the paper was in the use of the two equation-based k-eps turbulent model to predict the maximum heat transfer through optimum design of fins and duct.

scholarly journals Numerical Analysis of Mixed Convection through an Internally Finned Tube

2012 ◽  
Vol 4 ◽  
pp. 918342 ◽  
Author(s):  
Sachindra Kumar Rout ◽  
Dipti Prasad Mishra ◽  
Dhirendra Nath Thatoi ◽  
Asit Ku. Acharya
Keyword(s):  
Numerical Analysis ◽  
Mixed Convection ◽  
Finned Tube ◽  
Internally Finned Tube

Numerical Investigation of the Thermal Performance of an Axially Rotating Internally Finned Receiver Tube of Parabolic Trough Concentrator

2021 ◽  
Vol 16 ◽  
pp. 241-253
Author(s):  
Andrew S. Tanious ◽  
Ahmed A. Abdel-Rehim
Keyword(s):  
Thermal Performance ◽  
Rotation Rate ◽  
Pressure Coefficient ◽  
Axial Rotation ◽  
Finned Tube ◽  
Outlet Temperature ◽  
Parabolic Trough ◽  
Ansys Fluent ◽  
Fluid Layers ◽  
Internally Finned Tube

Enhancement of the thermal performance of the parabolic trough receiver tube is one of the approaches to energy sustainability. In the present work, the thermal performance of an axially rotating receiver tube equipped with internal flat longitudinal fins is studied. The effects of both the fin height and the rate of axial rotation are investigated at low values of axial Reynold’s number. The numerical analysis is held at various rotation rates using ANSYS Fluent. The numerical findings showed that the effect of the axial rotation on the internally finned receiver tube is not significant yet negative where a maximum reduction of 6% in the outlet temperature is reached in the 2mm height internally finned tube at rotation rate of N=21. However, the analysis showed that as the rotation rate increases, the temperature homogeneity between the fluid layers also increases and thus the liquid stratification phenomenon between the fluid layers is eliminated. The percentage of temperature difference between the fluid layers near the pipe center and the layers near the pipe wall reaches an optimum value of 58.4% at N=21 which is confirmed by an optimum increase of 110% in Nusselt number at the same rotation rate. However, a maximum loss of 81.6% in pressure coefficient is found in the case of the 2mm internally finned tube due to the increased turbulence. Thus, the integration of pipe axial rotation and internal fins can yield an enhancement in the heat transfer to the parabolic trough concentrator receiver tube and thus its thermal performance.

Experimental Study on the Identification of the Saturation of a Porous Media through Thermal Analysis

2014 ◽  
Vol 611-612 ◽  
pp. 1576-1583
Author(s):  
Maxime Villière ◽  
Sébastien Guéroult ◽  
Vincent Sobotka ◽  
Nicolas Boyard ◽  
Joel Breard ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Heat Flux ◽  
Porous Medium ◽  
Thermophysical Properties ◽  
Saturated Porous Medium ◽  
Homogenization Method ◽  
Saturation Curve ◽  
Mechanisms Of Formation ◽  
Mechanical Performances ◽  
The One

Resin Transfer Molding (RTM) is among the most commonly used fabrication processes for producing high quality and complex composite structural parts. RTM process consists of placing a dry fibrous preform into a mold cavity. A liquid resin is subsequently injected into that cavity. The consolidation of the part is then obtained by crosslinking in case of a thermosetting resin or by crystallization in case of thermoplastic one. Voids can be created in the porous medium during the flow of the resin. Presence of residual voids in the composite part at the end of the filling drastically affect mechanical performances. Even if several authors have contributed to a better understanding and modeling of the mechanisms of formation and transport of voids during injection, few experimental approaches allowed a direct measurement of the saturation curve. The aim of this study is then to identify the saturation of a fibrous preform by a liquid through thermal analysis. To address this issue, an experimental bench that allows the injection of a fluid into a textile preform has been used. This apparatus combines the measurement of temperatures and wall heat flux densities at several locations. A simplified modeling of the filling front has been performed with FEM using Comsol Multiphysics™. The saturation curve is modeled using several geometric parameters. Saturation is taken into account through the evolution of thermophysical properties. Effective thermophysical properties of the dry and completely-saturated porous medium in transverse and longitudinal directions have been measured by several methods, and their results have been then cross-checked and compared with good accuracy. The evolution between these two states has been modeled. A particular attention has been paid for the modeling of the transverse thermal conductivity. This parameter has been modeled using a periodic homogenization method as a function of the micro- and macro-saturation. The saturation curve parameters are determined by minimizing the cost function defined as the square difference between the measured and computed heat flux. The obtained saturation curve is finally compared with the one measured by a conductometric sensor.

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