Heat transfer problem for a long rectangular bar

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Discussion Overview

The discussion revolves around determining the temperature distribution in a long rectangular bar under steady-state conditions. The problem involves imposed heat flux at one face, convection at the opposing face, and fixed temperature at the remaining walls. Participants are exploring analytical solutions and methods for solving the governing differential equation with specified boundary conditions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant outlines the problem and seeks an analytical solution, mentioning the differential equation and boundary conditions but struggling with the superposition method.
  • Another participant points out that the original problem statement does not mention adiabatic walls, which were referenced in the superposition approach.
  • A third participant reiterates the lack of mention of adiabatic walls and clarifies their understanding of the superposition method being used.
  • One participant expresses support for the initial approach and inquires about handling the other two boundaries in the proposed cases.
  • Another participant suggests using three superposition cases instead of two, detailing the first case with insulated flux ends and proposing the use of separation of variables for the remaining cases.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the approach to the problem, with differing views on the use of adiabatic walls and the number of superposition cases needed. The discussion remains unresolved regarding the best method to find the temperature distribution.

Contextual Notes

There are limitations regarding the assumptions made about the boundary conditions, particularly concerning the mention of adiabatic walls and the specific handling of the boundaries in the proposed methods.

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Moved from a technical forum, so homework template missing
Summary:: Determine the temperature distribution in a bar (very long– 2D) with rectangular cross section, in steady state, with imposed flux at one face, convection at the opposing face (Tinf, h), and imposed temperature (T1) at the two remaining walls.

I am trying to find the analytical solution to the following problem :

Determine the temperature distribution in a bar (very long– 2D) with rectangular cross section, in steady state, with imposed flux at one face, convection at the opposing face (Tinf, h), and imposed temperature (T1) at the two remaining walls.

I have the differential equation and four boundary conditions , however I can't find the temperature distribution even using the supeposition method ( trying to find the solution with one of the walls adiabatic and the other transferring energy by convection and then finding the solution for one of the walls adiabatic and the other with imposed flux).

Has anyone came across a problem like this?
 

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Your figure matches the problem statement, but there are no adiabatic walls mentioned in the problem statement.
 
Chestermiller said:
Your figure matches the problem statement, but there are no adiabatic walls mentioned in the problem statement.
I was describing how i was using the superposition method
 
I like your approach. How do you handle the other two boundaries in each of the two cases?
 
You are on the right track. Instead of using 2 superpositions, use three. The first case is where T is equal to T1 everywhere and the flux ends are both insulated. The other two cases are the ones you already described, but with zero temperatures where T1 had been. These two other cases can be solved by separation of variables, with sine series in the x direction and hyperbolic sines and cosines in the y direction.
 

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