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Ashish February 24, 2009 07:05

Changing Heat transfer coefficient
 
I want to solve a transient conduction problem in which one wall boundary condition is defined in terms of heat transfer coefficient. As time passes heat transfer coefficient will change with respect to avg temp of that wall.(so i want to correlate avg temp of wall at the end of each time step to the heat transfer bc)
: > help

Thanks in advance.

Ralf Schmidt February 24, 2009 07:25

Re: Changing Heat transfer coefficient
 
go to

solve->monitors->surface

and set one surface monitor each time step for area weighted average Temperature at the wall and one surface monitor for area weighted average HTC.

Best wishes Ralf

Ashish February 24, 2009 07:51

Re: Changing Heat transfer coefficient
 
Thanks for help

BUT I THINK I FAILED TO COMMUNICATE- one of the thermal bc for conduction is HT coefficient and T ambient which will remain constant (there is only constant option in drop down menu next to it). But HT coefficient itself is a function of avg wall temp. (which is changing as i am solving transient problem) So i want to teach code to take avg wall temp at the end of first time step put that into some formula and put the newly calculated HTC as bc for next time step and so on

thanks


Ashish February 24, 2009 08:02

(PROBLEM IS UNSOLVED) *NM*
 

mange February 24, 2009 08:08

Re: (PROBLEM IS UNSOLVED)
 
Hi,

I think you have to code your function as a UDF. DEFINE_PROFILE i think should do the job. this way you can specify h as a function of whatever you want.

/M


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