Heat Conduction in a Cube: Calculating Temperature Over Time

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Discussion Overview

The discussion revolves around calculating the temperature distribution within a cube over time when heat is applied to one side. It explores theoretical and practical aspects of heat conduction, including boundary conditions and material properties.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant inquires about the method for calculating temperature at various distances into the cube over time.
  • Another participant suggests consulting the Wikipedia entry for heat conduction.
  • Concerns are raised about the non-linear flow of heat and the potential for heat loss from the sides of the cube.
  • A list of unknown variables is proposed, including material properties, initial temperature, heat application method, and cube dimensions.
  • A participant clarifies that the cube is not in a vacuum, starts at ambient temperature, and heat is applied to one full square side, complicating the use of Fourier's law due to heat loss.
  • Questions are posed regarding the governing differential equation for temperature as a function of time and distance, as well as the boundary conditions at the cube's faces.
  • One participant shares a practical experiment involving heating a cube of butter.
  • Another participant agrees on the relevance of the heat conduction differential equation and suggests that an analytical solution may not exist, recommending numerical methods or software like MATLAB or Mathematica.
  • A suggestion is made that finite element analysis (FEA) could provide an approximate solution.

Areas of Agreement / Disagreement

Participants express various viewpoints on the complexity of the problem, with some agreeing on the need for a mathematical model while others highlight the challenges posed by heat loss and boundary conditions. No consensus is reached on a specific method or solution.

Contextual Notes

Participants note several limitations, including the dependence on material properties, the specifics of heat application, and the potential for heat loss affecting calculations. The discussion does not resolve these complexities.

Who May Find This Useful

This discussion may be of interest to those studying heat conduction, mathematical modeling in physics, or practical applications in thermal dynamics.

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If heat is applied to one side of a cube, how can the temperature at different distances into the cube be calculated after different amounts of time have elapsed?
 
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Have you tried looking at the wikipedia entry for heat conduction?
 
but the flow of heat isn't linear it will escape from the sides of the cube
 
well? how can i solve?
 
There's a lot of unknown variables:

What material is the 'cube' made from?

what is the temperature starting?--how much is applied?

is it in a vacuum?

is the heat applied to a side? (where on the side?) or to a corner of the side?

how big is the cube?

What is the method of applying the heat?
 
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its not in a vacuum, its in air, it starts at the same temperature as the surroundings, the heat is applied to one full square side of the cube. If the sides of the cube were insulate then i could use Fourier's law however they are not so heat will be lost as it spreads throughout the cube at a different rate as the heated surface area will increase. It should be possible to calculate but I can't figure it out...
 
Since you're building a mathematical model for this,

- What's the differential which governs the temperature of the cube as a function of time and distance?
- What is the boundary condition at each of the faces of the cube? Is the heat influx constant at one face, or is the temperature kept constant?

Check the relevant chapters in your text. It should have what you're looking for.
 
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I just tried heating a cube of butter...
 
I agree with siddarth. This is the basic heat conduction differential equation with some specified material properties and boundary conditions. Refer to your textbook on how to set up the problem.

My guess is that the resulting partial differential equation won't have an analytical solution and you will need to use a numerical solver. If you are familiar with MATLAB or mathematica they should be able to meet your needs.
 
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  • #10
And, if you can accept an approximate answer, FEA is the easy way to do this.
 

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