Having issue with Film coefficient.

- January 29, 2019 at 5:44 pm
  
  Uday
  Subscriber
  
  Hello Everyone. I'm working on a project THERMITE WELDING OF RAIL. I wanted to find out Thermal stress inducing in rail ' I ' section due to THERMITE WELDING. As everyone knows the rail is ' I ' section. I'm applying 3088°c heat on one face and I wanted to see the temperature distribution within the ' I ' section. Have to apply CONDUCTION as well as CONVECTION at same time. Please help me to get out of this BLUNDER. Disparately waiting for reply. Thank you.
  
  Edit: rwoolhou. Moved to structural
- February 5, 2019 at 4:02 pm
  
  Sandeep Medikonda
  Ansys Employee
  
  Uday,
  
  It is not clear what the problem is here? Are you not able to pick a surface? Maybe an inline picture will help us understand?
  
  Regards,
  Sandeep
  Guidelines on the Student Community
- February 5, 2019 at 4:54 pm
  
  Uday
  Subscriber
  
  First of all I'm very thankful for your valuable reply.
  
  Sir we have take 6 meter long rail piece and we are applying temperature on its one face for 2 minutes . Temperature is around 3088°c . But when we apply convection to remaining rail , ANSYS ask for FILM COEFFICIENT value. What should we take that value?
  
  Desperately waiting for your help.
  
  Thank you.
- February 5, 2019 at 11:44 pm
  
  Bhargava Sista
  Ansys Employee
  
  Uday,
  
  The film coefficient or the heat transfer coefficient is the proportionality constant between the heat flux and the temperature difference. This value differentiates the properties of the surrounding fluid, for instance, heat flux would be different for stagnant air compared to flowing air or static/moving water. So, this depends on the nature of fluid to which the system is losing its heat to.
  
  In your case, if the rail is losing its heat to surrounding air, you'll need to find the appropriate value. Here's a link where they have listed the heat coefficient values for some scenarios.
  
  http://thermopedia.com/content/660/
  
  For your case, you may either go with free convection to air at 30 degrees C (5 W/m^2-K), or forced convection at low speed of airflow over the surface (10 W/m^2-K).
- February 6, 2019 at 12:17 am
  
  Uday
  Subscriber
  
  Thanks a lot for your reply.
  
  I have read the article and looks like we got the value of FILM COEFFICIENT. I will try to run simulation today only. Once done I will post the snap shot of results.
  
  Once again thanks a lot.
  
  Appreciate your help.