CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > General Forums > Main CFD Forum

Heating of a solid cylinder with internal heat generation

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   July 13, 1999, 16:17
Default Heating of a solid cylinder with internal heat generation
  #1
Sriram Popuri
Guest
 
Posts: n/a
Hi! I have a two dimensional transient heat conduction problem with internal heat generation (exponentially decaying (axially) heat source). It's a solid cylinder. I am looking for qualitative data (temperature profiles) inside the cylinder. This is a pure conduction problem. But, I was wondering if I could use Fluent 4.5 or 5.0(somehow) to get the results quickly in a short time. If someone could give me a probable answer, I sincerely appreciate it. Thanks!
  Reply With Quote

Old   July 13, 1999, 16:47
Default Re: Heating of a solid cylinder with internal heat generation
  #2
Adrin Gharakhani
Guest
 
Posts: n/a
Maybe I'm missing something here, but if the problem is 2D how is the heat source axial? Do you mean radial?

If the boundary condition is not too complex, you can take advantage of the symmetry (and the simplicity) of the geometry and derive the (semi) analytical solution for your problem. Any graduate level book on conduction will talk about various problems (BC's) related to cylinders. You may actually find your exact problem solved in these books.

Adrin Gharakhani
  Reply With Quote

Old   July 13, 1999, 17:42
Default Re: Heating of a solid cylinder with internal heat generation
  #3
Sriram Popuri
Guest
 
Posts: n/a
Hi, Adrin! Thanks for replying. May be I will explain the problem formulation in a little better detail now. The formulation is an over simplification of the actual physical problem. The actual problem involves microwave heating (internal heating) of a compound medium with cylindrical structure (effective properties and power attenuation constants, I have defined with reasonable assumptions). The temp gradients are functions of x and r only. So, at time zero the power flux starts heating one face and decays towards the outlet exponenentially (is a function of x). The power flux will not appear as a boundary condition. The bcs are convective and for simplicity are made zero from all the faces. Of course, I have the symmetry condition at the center line. So, that's basically the problem. I need to find out the axial temp. profiles for t>0 by varying power flux at the inlet. Sounds simple enough. I looked into several grad level conduction texts (including Necati Ozisik's). Ozisik talks about a similar problem. But the solution process, I thought, was too complex. Anyways, if you could give me any further simplifying ideas, I appreciate that. Thanks!
  Reply With Quote

Old   July 13, 1999, 18:08
Default Re: Heating of a solid cylinder with internal heat generation
  #4
Tom Plikas
Guest
 
Posts: n/a
In fluent 5.1.1, you can define a user defined scalar equation. Write user defined functions in C using DEFINE_DIFFUSIVITY and DEFINE_SOURCE (see help section for details) to describe your thermal diffusivity and volumetric heat source respectively. In the user defined scalars pane,, you set the flux function equal to none and allow for the default unsteady function (Fluent 5.1.1 has this option). You now have a unsteady conduction problem with a source term. After properly defined your B.C.'s, turn off the flow equations in solution controls panel so that you just solve the scalar equation. Although I have not tried the above mentioned procedure, this should work Good luck Tom
  Reply With Quote

Old   July 13, 1999, 18:16
Default Re: Heating of a solid cylinder with internal heat generation
  #5
Sriram Popuri
Guest
 
Posts: n/a
Thanks, Tom! I don't have Fluent 5.0 not 5.1.1, but I am assuming it's possible with 5.0 also. I will take a look at that.
  Reply With Quote

Old   July 13, 1999, 18:21
Default Re: Heating of a solid cylinder with internal heat generation
  #6
Tom Plikas
Guest
 
Posts: n/a
I don't think Fluent 5.0 allows for a unsteady term in the scalar equation. Fluent 5.1 does. You'll have to check.
  Reply With Quote

Old   July 13, 1999, 19:09
Default Re: Heating of a solid cylinder with internal heat generation
  #7
Sriram Popuri
Guest
 
Posts: n/a
Tom! I only use Fluent 4.5; I will take your word for it about 5.0. I will try to get 5.1 if I could. thanks
  Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
UDF for heat generation prince_pahariaa FLUENT 4 July 11, 2011 03:58
UDF for heat generation prince_pahariaa Fluent UDF and Scheme Programming 0 July 7, 2011 07:04
Constant velocity of the material Sas CFX 15 July 13, 2010 09:56
heat conducting in a solid domain Rogerio Fernandes Brito FLUENT 0 March 18, 2008 18:25
CFX4.3 -build analysis form Chie Min CFX 5 July 13, 2001 00:19


All times are GMT -4. The time now is 03:48.