Convection coefficient h
Posted: Thu Jun 01, 2017 9:38 am
Hello,
I'm doing a very simple simulation of a flow around an object and I would like to compare the convection coefficient from the theory and my simulation.
Case : I have a flow with a velocity of 4m/s, with a pressure of 5 bars, and a temperature of 180°C.
The object has a constant temperature of 80°C. (cf picture)
I did a 2D mesh (my block is 0.4m * 0.15m * 0.001m and the two faces with the normal z have symmetry condition)
I am wondering how to determine h ?
My first guess was to use the input thermal flux (Phi) such as h=Phi/(180-80).
But I dont know if Phi is in W/m² or in W. But then I saw that the boundary temperature was not exactly equal to 80°C, it's in fact varying from 82°C to 112°C.
1) Is the input thermal flux in W or in W/m² ?
2) Shall I use the boundary temperature instead of 80°C ?
3) Shall I use the fluid temperature at the boundary instead of 180°C ?
Thank you,
Regards,
Quentin
I'm doing a very simple simulation of a flow around an object and I would like to compare the convection coefficient from the theory and my simulation.
Case : I have a flow with a velocity of 4m/s, with a pressure of 5 bars, and a temperature of 180°C.
The object has a constant temperature of 80°C. (cf picture)
I did a 2D mesh (my block is 0.4m * 0.15m * 0.001m and the two faces with the normal z have symmetry condition)
My first guess was to use the input thermal flux (Phi) such as h=Phi/(180-80).
But I dont know if Phi is in W/m² or in W. But then I saw that the boundary temperature was not exactly equal to 80°C, it's in fact varying from 82°C to 112°C.
1) Is the input thermal flux in W or in W/m² ?
2) Shall I use the boundary temperature instead of 80°C ?
3) Shall I use the fluid temperature at the boundary instead of 180°C ?
Thank you,
Regards,
Quentin