scholarly journals Analysis of Convective Straight and Radial Fins with Temperature-Dependent Thermal Conductivity Using Variational Iteration Method with Comparison with Respect to Finite Element Analysis

2007 ◽  
Vol 2007 ◽  
pp. 1-15 ◽  
Author(s):  
Safa Bozkurt Coşkun ◽  
Mehmet Tarik Atay
Keyword(s):  
Thermal Conductivity ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Iteration Method ◽  
Variational Iteration Method ◽  
Large Temperature ◽  
Temperature Dependent ◽  
Element Analysis ◽  
Variational Iteration ◽  
Temperature Dependent Thermal Conductivity

In order to enhance heat transfer between primary surface and the environment, radiating extended surfaces are commonly utilized. Especially in the case of large temperature differences, variable thermal conductivity has a strong effect on performance of such a surface. In this paper, variational iteration method is used to analyze convective straight and radial fins with temperature-dependent thermal conductivity. In order to show the efficiency of variational iteration method (VIM), the results obtained from VIM analysis are compared with previously obtained results using Adomian decomposition method (ADM) and the results from finite element analysis. VIM produces analytical expressions for the solution of nonlinear differential equations. However, these expressions obtained from VIM must be tested with respect to the results obtained from a reliable numerical method or analytical solution. This work assures that VIM is a promising method for the analysis of convective straight and radial fin problems.

scholarly journals Modified variational iteration method for straight fins with temperature dependent thermal conductivity

2018 ◽  
Vol 22 (Suppl. 1) ◽  
pp. 229-236 ◽  
Author(s):  
Mustafa Inc ◽  
Hasib Khan ◽  
Dumitru Baleanu ◽  
Aziz Khan
Keyword(s):  
Thermal Conductivity ◽  
Iteration Method ◽  
Adomian Decomposition Method ◽  
Variational Iteration Method ◽  
Temperature Dependent ◽  
Convergence Region ◽  
Variational Iteration ◽  
Adomian Decomposition ◽  
Temperature Dependent Thermal Conductivity ◽  
Modified Variational Iteration Method

The modified variational iteration method (MVIM) has been used to calculate the efficiency of straight fins with temperature dependent thermal conductivity. The obtained results are compared with homotopy analysis method (HAM), homotopy perturbation method (HPM), and Adomian decomposition method (ADM). It is used w ? 0 auxiliary parameter to keep under control convergence region of solution series in MVIM. As a result, although MVIM and HAM give results close to each other; HPM and ADM give divergent results from analytical solution.

scholarly journals Variational iteration method to solve moving boundary problem with temperature dependent physical properties

2011 ◽  
Vol 15 (suppl. 2) ◽  
pp. 229-239 ◽  
Author(s):  
Jitendra Singh ◽  
Kumar Gupta ◽  
Nath Rai
Keyword(s):  
Thermal Conductivity ◽  
Physical Properties ◽  
Specific Heat ◽  
Boundary Problem ◽  
Iteration Method ◽  
Moving Boundary ◽  
Variational Iteration Method ◽  
Moving Boundary Problem ◽  
Temperature Dependent ◽  
Variational Iteration

In this paper, variational iteration method is used to solve a moving boundary problem arising during melting or freezing of a semi infinite egion when physical properties (thermal conductivity and specific heat) of the two regions are temperature dependent. The Result is compared with result obtained by exact method (when thermal conductivity and specific heat in two regions are temperature independent) and semi analytical method (When thermal conductivity and specific heat are temperature dependent) and are in good agreement. We obtain the solution in the form of continuous functions. The method performs extremely well in terms of efficiency and simplicity and effective for solving the moving boundary problem.

Micro-structurally informed finite element analysis of carbon/carbon composites for effective thermal conductivity

2019 ◽  
Vol 226 ◽  
pp. 111221 ◽  
Author(s):  
Mohammad Zahid ◽  
Rajneesh Sharma ◽  
Atul Ramesh Bhagat ◽  
Syed Abbas ◽  
Ajay Kumar ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Effective Thermal Conductivity ◽  
Carbon Composites ◽  
Element Analysis

Finite Element Analysis of the Effect of Particle Shape on the Thermal Conductivity in Diamond/Cu Composites

2014 ◽  
Vol 788 ◽  
pp. 689-692
Author(s):  
Hong Guo ◽  
Yuan Yuan Han ◽  
Xi Min Zhang ◽  
Fa Zhang Yin ◽  
Ye Ming Fan ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Finite Element Method ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Resistance ◽  
Particle Shape ◽  
Finite Element Calculation ◽  
Element Calculation ◽  
Element Analysis ◽  
Result Show

The effect of diamond shape on the thermal conductivity of diamond/Cu composites was studied by combine finite element method with the tests. The finite element result show that the thermal conductivity of the hexoctahedron diamond/Cu composites and the square diamond/Cu composites is 819 W/m·K and 1013 W/m·K respectively. And the testing results indicate that the thermal conductivity of the single hexoctahedron diamond/Cu composites and the hexoctahedron mixed with the square diamond/Cu composites is 659W/m·K and 720 W/m·K respectively. The testing results consist with the finite element calculation. Under the same circumstances, more {100} faces can bring in less overall thermal resistance in the composites thus improve the thermal conductivity of the composites. The results show that using square diamond particles helps to improve the thermal conductivity of diamond/Cu composites.

Thermal-Electric Finite Element Analysis of Electrosurgical Cautery Process

2007 ◽  
Author(s):  
Robert E. Dodde ◽  
Scott F. Miller ◽  
Albert J. Shih ◽  
James D. Geiger
Keyword(s):  
Heat Transfer ◽  
Electrical Conductivity ◽  
Finite Element ◽  
Biological Tissue ◽  
Tissue Temperature ◽  
Temperature Dependent ◽  
Element Analysis ◽  
Temperature Dependent Thermal Conductivity ◽  
Insight Into ◽  
Good Agreement

Cautery is a process to coagulate tissues and seal blood vessels using the heat. In this study, finite element modeling (FEM) was performed to analyze temperature distribution in biological tissue subject to cautery electrosurgical technique. FEM can provide detailed insight into the heat transfer in biological tissue to reduce the collateral thermal damage and improve the safety of cautery surgical procedure. A coupled thermal-electric FEM module was applied with temperature-dependent electrical and thermal properties for the tissue. Tissue temperature was measured at different locations during the electrosurgical experiments and compared to FEM results with good agreement. The temperature-dependent electrical conductivity has demonstrated to be critical. In comparison, the temperature-dependent thermal conductivity does not impact heat transfer as much as the electrical conductivity. FEM results show that the thermal effects can be varied with the electrode geometry that focuses the current density at the midline of the instrument profile.

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