August 8, 2024 at 5:33 pm
Abdullah Hassan
Bbp_participant

Thankyou so much Sir. I learned alot while communicating with you in this thread.

I have a last question. 

As you know, I have defined Heat flux (-5858W/m2) value at tubewall:1 (heat flux tube fluid should absorb). And by changing temperature at reference values tab, I am also able to achieve heat transfer coefficient(+ve) and heat flux (-ve) at boundaries in vapor domain.  
but when I checked volume integrals, the heat flux at the tube wall is +ve and heat transfer coefficient due to heat flux becomes negative. 

1- why tubewall:1 & tube wall in both surface & volume integrals have opposite signs. 

2- why -5858W/m2 is not reflecting at volume integral > tube wall ? 

Is there anyway, I can calculate or understand heat flux calculations or what properties are really effecting it like for heat transfer coefficinet it is heff = q/Twall - Tref.