Variable Thermal Conductivity Heat Transfer With Symbolic Algebra

Author(s):  
A. Aziz

This paper deals with the analysis of heat transfer in media with variable thermal conductivity. The tool employed is the symbolic algebra package Maple. The specific problems considered are (1) steady conduction in a heat generating plane wall with thermal conductivity increasing as the square of the coordinate, (2) steady conduction in a circular rod with axially varying thermal conductivity exposed to a cross flow stream, (3) steady conduction in a hollow cylindrical shell with simultaneous coordinate and temperature dependent thermal conductivity, (4) steady conduction in a two-layered hollow cylindrical shell with the thermal conductivity of the inner shell varying linearly with the radial coordinate and the thermal conductivity of the outer shell varying linearly with temperature, (5) two-dimensional steady conduction in an orthotropic plate with different thermal conductivities along the two axes, and (6) transient conduction in a plane wall with coordinate dependent thermal conductivity. The paper demonstrates the effectiveness of the software that is capable of producing analytical solutions for problems that are very cumbersome to solve by hand, and at the same incorporates powerful numerical and graphical capabilities for solving problems that are analytically intractable. The paper should not be perceived as a commercial endorsement of Maple.

2011 ◽  
Vol 15 (suppl. 1) ◽  
pp. 111-115 ◽  
Author(s):  
Domiri Ganji ◽  
Ziabkhsh Ganji ◽  
Domiri Ganji

In this paper, homotopy perturbation method has been used to evaluate the temperature distribution of annular fin with temperature-dependent thermal conductivity and to determine the temperature distribution within the fin. This method is useful and practical for solving the nonlinear heat transfer equation, which is associated with variable thermal conductivity condition. The homotopy perturbation method provides an approximate analytical solution in the form of an infinite power series. The annular fin heat transfer rate with temperature-dependent thermal conductivity has been obtained as a function of thermo-geometric fin parameter and the thermal conductivity parameter describing the variation of the thermal conductivity


2016 ◽  
Vol 71 (12) ◽  
pp. 1105-1110
Author(s):  
H.Q. Kafri ◽  
S.A. Khuri ◽  
Ali Sayfy

AbstractThis article introduces a new numerical approach to solve the equation that models a rectangular purely convecting fin with temperature-dependent thermal conductivity. The algorithm embeds an integral operator, defined in terms of Green’s function, into Krasnoselskii–Mann’s fixed point iteration scheme. The validity of the method is demonstrated by a number of examples that consist of a range of values of the parameters that appear in the model. In addition, the evaluation of the fin efficiency is presented. The residual error computations show that the current method provides highly accurate approximations.


2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
R. M. S. Gama ◽  
R. Pazetto

This work presents an useful tool for constructing the solution of steady-state heat transfer problems, with temperature-dependent thermal conductivity, by means of the solution of Poisson equations. Specifically, it will be presented a procedure for constructing the solution of a nonlinear second-order partial differential equation, subjected to Robin boundary conditions, by means of a sequence whose elements are obtained from the solution of very simple linear partial differential equations, also subjected to Robin boundary conditions. In addition, an a priori upper bound estimate for the solution is presented too. Some examples, involving temperature-dependent thermal conductivity, are presented, illustrating the use of numerical approximations.


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