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

Brake Rotor Thermal Calculation in STAR-CD- Urgent

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

Reply
 
LinkBack Thread Tools Display Modes
Old   June 20, 2006, 01:47
Default Brake Rotor Thermal Calculation in STAR-CD- Urgent
  #1
ps
Guest
 
Posts: n/a
I am a fluent user and have a small query regarding the solving procedure of a problem In STAR-CD which involves fluid flow over the solid and the conduction within the solid (for ex: thermal calculations of the brake rotor, which involves flow over the brake rotor and the heat conduction with in the brake rotor)

In Fluent, for this problem, first we simulate the flow over the brake rotor and find the convective heat transfer coefficients. Then we deactivate the fluid volume (fluid domain around the brake rotor) and make only the solid volume (rotor solid) active. Then we run only the energy equation with in the solid by using the convection values obtained from the fluid flow simulation. By deactivating the fluid volume, which is not needed while solving for the conduction within the solid rotor, we can save CPU time.

Is this possible in STAR-CD. Can we deactivate the fluid volume and make only the solid volume activate in STAR-CD, which is possible in Fluent.

In Fluent, if we want, we can toggle of the Flow and can run only the Energy equation, which helps in saving the CPU Time. Is this option available in STAR-CD

Please let me know whether these options are available in STAR-CD. If these options are not available, then when is the best possible way in STAR-CD to solve the above problem by saving the CPU run time?

Your immediate response/help in this regard is highly appreciated.

Thanking You

  Reply With Quote

Old   June 20, 2006, 02:54
Default Re: Brake Rotor Thermal Calculation in STAR-CD- Ur
  #2
steve
Guest
 
Posts: n/a
It is possible in STAR-CD to freeze the flow/turbulence field and solver for temperature only.

I am not sure why you would really want to do this since the expensive part of the calculation ,especially when you do radiation is not the temperature, it is the flow.

One thing that is important is to check that the solid URF for temperature is set correctly. I have done a few calculations myself and have now started using STAR-CCM+ v2 for such a calculations I have to increase the solid temperature URF from 0.9 to some value close to one (or 1 if I have a perfect grid). STAR-CD 3.26 has a solid shell URF of 1.0 and this ensures that the solid converges in temperature fast.

I hope this helps.
  Reply With Quote

Old   June 21, 2006, 07:31
Default Re: Brake Rotor Thermal Calculation in STAR-CD- Ur
  #3
William Blake
Guest
 
Posts: n/a
There is a good reason to go this way. First calculate the flow steady state and after this use the frozen flow field for a transient temperature calculation with large timesteps.

  Reply With Quote

Old   June 27, 2006, 04:18
Default Unsteady Solid Condution solving in STAR-CD
  #4
STAR-USER
Guest
 
Posts: n/a
Hi All!

I have a small query regarding the Solid conduction problem solution in STAR-CD. This is an unsteady problem and my aim is to find the temperature variation of that solid with time by dissipating the heat by convection. I enter the heat trainsfer coefficients values.

Please let me know how to calculate the time step in solid conduction problems, where as we calculate the time step based on CFL in case of a fluid. I have to simulate for a long time. can I enter the big time steps and any condition to be validated like CFL in case of fluids.

Is there any care to be taken in relaxation factors and any other text interface commands to be enterred in this condution problem in STAR-CD.

Your help in this regard is highly appreciated
  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
rotor brake mAx FLUENT 0 September 13, 2006 01:47
Thermal conductivity (Urgent) ck1973 FLUENT 1 June 10, 2006 23:54
flux calculation(urgent) vid FLUENT 3 February 21, 2006 04:18
Force calculation - Urgent Please AP CD-adapco 6 January 17, 2006 10:22
STAR-CD underhood thermal management Sener Yilmaz CD-adapco 15 February 3, 2000 16:56


All times are GMT -4. The time now is 07:22.