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radiation direction boundary conditions
Posted 2010/12/14 2:12 GMT-5 1 Reply
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Hi everybody
I need to understand what is the different between radiation direction boundary conditions which are Positive normal direction, Negative normal direction And Opacity controlled. I am using comsol 4a version.
I have read the heat transfer interfaces section. But I still cannot recognize what is the real different among them. I thought in the beginning if I specify the positive normal direction boundary condition for a surface. That surface will emit radiation just in normal direction and anything not in normal will not affect. But that not true.
Please take a look at the attached file “Rapid Thermal Annealing module “
Please could anyone explain more what is different between them?
I need to understand what is the different between radiation direction boundary conditions which are Positive normal direction, Negative normal direction And Opacity controlled. I am using comsol 4a version.
I have read the heat transfer interfaces section. But I still cannot recognize what is the real different among them. I thought in the beginning if I specify the positive normal direction boundary condition for a surface. That surface will emit radiation just in normal direction and anything not in normal will not affect. But that not true.
Please take a look at the attached file “Rapid Thermal Annealing module “
Please could anyone explain more what is different between them?
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1 Reply Last Post 2010/12/14 5:40 GMT-5
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Posted:
1 decade ago
Hi
to view the normal use a surface arrow plot and plot the "definition base vector normal vector n (nx.ny.nz)" which defines the positive direction (away from the material for boundaries)
I understand that "opacity" is used when you have aborbing medium between the surfaces (which is not your case believe). But this should be tested on a simple model, I havent tried and verified/validated radiative exchange in v4.1 myself yet ;)
--
Good luck
Ivar
to view the normal use a surface arrow plot and plot the "definition base vector normal vector n (nx.ny.nz)" which defines the positive direction (away from the material for boundaries)
I understand that "opacity" is used when you have aborbing medium between the surfaces (which is not your case believe). But this should be tested on a simple model, I havent tried and verified/validated radiative exchange in v4.1 myself yet ;)
--
Good luck
Ivar