Heat Transfer Finite Difference Modeling

[QMax1]

I'm looking for a program that models the temperature profile around a pipewall and into the process with a heat source at one point. I would need to be able to easily vary the pipe diameter, thickness and size and temperature of the heat source. I've done some research and have found some expensive programs to do this (ANSYS, FloTHERM, WinTherm).

Anyone have experience with an inexpensive and easy to use programs for this purpose?

Many thanks!

 

[DanStro]

If your somewhat proficient at programming you can use Matlab.

or

There another program FlexPDE that can do this.

Both are pretty cheap compared to the codes that you mentioned. But you'll probably need to do some coding to get them to do exactly what you want.

There are a couple of free matlab-like clones (GNU Octave, FreeMat, and Scilab) that probably can do this too.

I don't know of any FEA codes that would be easy to setup that are either much cheaper (or free), perhaps Caculix but I've never used it to solve heat transfer problems so I can't say.

HTH
Dan

 

[sailoday28]

What do you mean by heat source at a point?
Is the heat flow in one dimension (radially)?

 

[gwolf2]

I've also coded this sort of thing using Excel. The I/O and display are done using the spreadsheet and the iteration using VBA.

 

[QMax1]

DanStro - Thanks for the leads. I'll check these out.

Sailoday - trying to model heat transfer from a steam tracer around a pipewall and into process (all inside insulation). Just looking for 1-dimensions right now, but it would need to be multi-layered to account for the various film coefs and the conduction through the insulation, tube wall and pipe wall.

 

[wimple]

hello

You can program it using Finite Difference Method described in Suhas V. Patankar Book. you could use Fortran as the book contains sample programs in this language.

You could use one dimension model as the pipe is symetric. You would consider a segment with a set of discrete nodes located at equal distances and separated by half this distance on extremities. you write the Fourier differential heat equation (in radial coordinate system) and compute a finite difference discretization scheme in order to constitue a set of algebric equations.

For boundary conditions, On one extremity node (center of pipe) the symetry condition should apply. On the other I guess should set the Outside Temperature T=Ts. The heat sink (S) should stand for the RHS of the discrestized algebric equations.

When the Finite difference set of equation is available, it is possible to solve via TDMA algorithm described in Patankar's Book. However Still remain the option to use an iterative method as well.

As far as I know, ANSYS use finite element formalism to solve heat transfer problems.

Hope it helps
Regards
Wimple

 

[stanford94]

i think there's something on this in "Numerical Recipes"... good book. (fortran)

 

[sailoday28]

With symmetry is this the radial heat transfer problem?

insulation/|heat tracing |pipe wall | fluid to cnt line|

Or are there more layers?

 

[corus]

For steady state temperatures you should be able to get an analytical solution, unless you have temperature dependent properties or non-linear boundary conditions, otherwise you should be able to get a good commercial FE program for free that has limited number of nodes available (300 typically)or has a limited period of use. For a 1D case you won't need many nodes anyway.

corus

 

[TERIO]

As others have said, if you don't mind programming this is not to hard to code yourself (certainly cheaper than buying ANSYS if this is the only thing you want to do).

I believe people sometimes use analytical solutions (infinite series) for 1-D transient heat transfer in slabs; there are probably charts for various Biot number and Fourier numbers in your favorite heat transfer book.

Specific to transient heat transfer in pipes I have heard of (but never used myself) something called the Brock-McNeill charts:

McNeill, D. R. and Brock, John E., “Engineering Data File Charts for Transient Temperatures in Pipes,” Heating/Piping/Air Conditioning, Reinhold Publishing Company,
November 1971.

Not sure where you would be able to find this reference.

 

[zekeman]

If you could provide a drawing of your problem, maybe a we can find an analytical expression for it, a lot cheaper than those "expensive" 'bulldozer' programs.