Temperature distribution with heat generation

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Discussion Overview

The discussion revolves around solving a heat transfer problem involving temperature distribution in a one-dimensional system with two different materials (an electric wire and rubber) and heat generation. Participants are exploring the mathematical approach to find the temperature distribution from 0 to 2L, considering boundary conditions and material properties.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Technical explanation

Main Points Raised

  • One participant presents a homework problem involving two materials with different thermal conductivities and asks for help in finding the temperature distribution.
  • Another participant notes that the heat flux must be continuous at the interface between the two materials.
  • There is a discussion about the implications of the boundary condition at x=0, where the temperature is maintained at 500 K, suggesting that the boundary is insulated.
  • Participants express uncertainty about calculating constants in their equations, particularly the constant related to the region with different thermal conductivity.
  • One participant mentions having found a general form of the temperature distribution but is unsure about the temperature at the interface.
  • There is a suggestion that one of the constants (C1) may equal zero, prompting further inquiry into whether this helps complete the solution.

Areas of Agreement / Disagreement

Participants express uncertainty and do not reach a consensus on how to proceed with the calculations, particularly regarding the constants in their equations and the implications of the boundary conditions.

Contextual Notes

Participants are working with assumptions about heat generation and material properties, but there are unresolved aspects regarding the continuity of heat flux and the specific values of constants in their equations.

noName2
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hey i really need help with solving this question.

1. Homework Statement


the problem is in one dimension x ( 2 plates with diffrent K joined together)
for x=0 T=500 ( constat temp)
0<x<L - electric wire is generating heat that maintane the constant temp in x=0 ,it has K=40W/mK.
L<x<2L - there is rubber preventing electriciution and heat loss Ki= 0.2 W/Km , where T(2L)=300K(constant).

how do i find the tempreture distribiotion in the 0<x<2L? (q* gen should be unknown but expressed in the finle answer)
please help :(

Homework Equations


foriers' law of conduction & Qin-Qout+Qgen=Qacc

The Attempt at a Solution



i can find the distribution using the heat balance integral.. but I am not sure about the temperature at x=L..
 
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noName2 said:
hey i really need help with solving this question.

1. Homework Statement


the problem is in one dimension x ( 2 plates with diffrent K joined together)
for x=0 T=500 ( constat temp)
0<x<L - electric wire is generating heat that maintane the constant temp in x=0 ,it has K=40W/mK.
L<x<2L - there is rubber preventing electriciution and heat loss Ki= 0.2 W/Km , where T(2L)=300K(constant).

how do i find the tempreture distribiotion in the 0<x<2L? (q* gen should be unknown but expressed in the finle answer)
please help :(

Homework Equations


foriers' law of conduction & Qin-Qout+Qgen=Qacc

The Attempt at a Solution



i can find the distribution using the heat balance integral.. but I am not sure about the temperature at x=L..
Let's see what you've done so far?

Chet
 
well , i found the general form of the distribution of the electric wire area(0<x<L) but I am missing a constant because I am not sure what's the temprature in the middle.
i was asked to find the distribution from 0<x<2L ..so i don't know if what i did is right..

here's what i did (image ) :http://www.imageurlhost.com/di/NME6/-.png
 
anyone?
 
The flux has to be continuous at the interface.

Chet
 
i know that..
 
If the electrical wire is generating just enough heat to maintain the boundary at x = 0 constant at 500 K, to me that means that the boundary at x = 0 is essentially insulated (i.e., no external heat flux required). What does that mean with regard to the constant C2 in your equation?

Chet
 
Last edited:
i know that constant i wrote in my answer that it is equal to T0. problem is the c1. i have no idea how to calculate it becase the other side of it has a diffrent k and has no heat generation.even if i compere heat flux. what shall i do ? I've tried everything!
 
noName2 said:
i know that constant i wrote in my answer that it is equal to T0. problem is the c1. i have no idea how to calculate it becase the other side of it has a diffrent k and has no heat generation.even if i compere heat flux. what shall i do ? I've tried everything!
Oh. Sorry. I meant C1 in post #7, not C2.

Chet
 
  • #10
C1 = 0. With this new added information, do you think you will be able to complete the solution?
 
Last edited:

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