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

Solid Timescale Control

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

Reply
 
LinkBack Thread Tools Display Modes
Old   August 22, 2007, 09:09
Default Solid Timescale Control
  #1
Parthipan
Guest
 
Posts: n/a
Dear all,

I am modelling a solid-solid CHT model in CFX. It consists of an inner volume and an outer bounding volume. The inner volume is the source of heat and I want to see the heat transfer in the outer volume. I have specified the inner volume as source with the Total source value in Watts.

After Performing a steady state calculation, I find that the temperature is very high than expected using a Auto Timescale in the Solid Timescale Control Tab.

I did the calculation again with the following settings with different values of 1s, 10s and 50s

Output control -> Solid Timescale Control -> Physical Timescale -> ___

These too gave a result far away from my expected results.

This time, I tried the calculation agian with

Output control -> Solid Timescale Control -> Physical Timescale -> 0.1 s

Now the Temperature is very near to my expected values.

1. How could I come to a conclusion with my Physical Timescale for the solid?

2. What if in a new case, I don't know the expected temperature to compare with?

Waiting for your replies.......

Thank you.
  Reply With Quote

Old   August 22, 2007, 18:10
Default Re: Solid Timescale Control
  #2
Glenn Horrocks
Guest
 
Posts: n/a
Hi,

Are you sure it has fully converged? In CHT simulations activating the imbalance convergence criteria is often useful. This often converges much slower than the residuals for CHT simulations.

You can judge whether it is going to have an effect by looking at the global imbalances in the output file.

Glenn Horrocks
  Reply With Quote

Old   August 24, 2007, 10:07
Default Re: Solid Timescale Control
  #3
Parthipan
Guest
 
Posts: n/a
Hai Glenn,

All the solutions have converged. What I wanted to do was a transient simulation. I wanted a initial file for my transient simulation, which had to be done by a steady state simulation. When I apply the same boundary conditions and run the simulation, the temp. shoots up to a very high value at the point of convergence. In advice from one of my collegaue I have taken off all the sources and done a steady state solution. And this I have used it for my transient simulation.
  Reply With Quote

Reply

Thread Tools
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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
CFX doesn't continue calculation... mactech001 CFX 6 November 15, 2009 22:25
increasing mesh quality is leading to poor convergence tippo CFX 2 May 5, 2009 10:55
SST in 2D? Jesper Sørensen CFX 16 December 23, 2006 09:40
Convective Heat Transfer - Heat Exchanger Mark CFX 6 November 15, 2004 16:55
CFX4.3 -build analysis form Chie Min CFX 5 July 12, 2001 23:19


All times are GMT -4. The time now is 13:03.