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heat flux in subdomains
Posted 19 oct. 2009, 15:47 UTC−4 1 Reply
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Goodmorning everybody. I'm using Comsol to modelize the temperature field of a quiescent volcano. I'm using the application mode "heat transfer- transient conduction and convection" in 2D, axial simmetry. I have a problem: I need to impose an heat flux of a certain value, for exemple 2500 J/sm^2, in a singular subdomain: substantially I want to impose a vertical flux into the volcano conduit, that i have modelized by a subdomain of rectangular shape. I don't manage to do it, can you help me? thank you very much
1 Reply Last Post 19 oct. 2009, 17:44 UTC−4
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Posted:
1 decade ago
Hi
I get always slightly confused with the 2*pi*r multipicand to apply to axisymmetric models therefore I always check out my cases on some simple geometries.
Most source term for a volume is defines as W/m^3, this should then take into the account the 2*pi*r t give a homogenious source, even f r=0 on the axis, when defining the source on a surface (of revolution) in axisymmetry.
If you intend to apply a surface source on the radial edge (of revolution), you must define it as W/m^2 and again I believe this should take into account the case r=0 correctly.
COMSOL behaves slightly differenly in Structural 2D axisymmetry, where you have the option to multiply by 2*pi*r with a "click setting" which changes the Force load case units from N/m (respective to the edge) to N/m^2 (when you consider the edge as a surface by revolution).
so for me:
, subdomain = volume = represented as a surface*2*pi*r in axisymmetry = [W/m^3] (and W=J/s)
, and
, boundary = surface = represented as an edge*2*pi*r in axisymmetry = [W/m^2]
Hope this helps, pls check carefully
Good luck
Ivar
I get always slightly confused with the 2*pi*r multipicand to apply to axisymmetric models therefore I always check out my cases on some simple geometries.
Most source term for a volume is defines as W/m^3, this should then take into the account the 2*pi*r t give a homogenious source, even f r=0 on the axis, when defining the source on a surface (of revolution) in axisymmetry.
If you intend to apply a surface source on the radial edge (of revolution), you must define it as W/m^2 and again I believe this should take into account the case r=0 correctly.
COMSOL behaves slightly differenly in Structural 2D axisymmetry, where you have the option to multiply by 2*pi*r with a "click setting" which changes the Force load case units from N/m (respective to the edge) to N/m^2 (when you consider the edge as a surface by revolution).
so for me:
, subdomain = volume = represented as a surface*2*pi*r in axisymmetry = [W/m^3] (and W=J/s)
, and
, boundary = surface = represented as an edge*2*pi*r in axisymmetry = [W/m^2]
Hope this helps, pls check carefully
Good luck
Ivar